WO2020075425A1 - Magnetic sensor and method for manufacturing magnetic sensor - Google Patents

Magnetic sensor and method for manufacturing magnetic sensor Download PDF

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Publication number
WO2020075425A1
WO2020075425A1 PCT/JP2019/035027 JP2019035027W WO2020075425A1 WO 2020075425 A1 WO2020075425 A1 WO 2020075425A1 JP 2019035027 W JP2019035027 W JP 2019035027W WO 2020075425 A1 WO2020075425 A1 WO 2020075425A1
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Prior art keywords
magnetic
layer
film magnet
hard
thin
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PCT/JP2019/035027
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French (fr)
Japanese (ja)
Inventor
大三 遠藤
竜徳 篠
栄久 大橋
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昭和電工株式会社
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Publication of WO2020075425A1 publication Critical patent/WO2020075425A1/en

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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R33/00—Arrangements or instruments for measuring magnetic variables
    • G01R33/02—Measuring direction or magnitude of magnetic fields or magnetic flux
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N—ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N50/00—Galvanomagnetic devices
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N—ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N50/00—Galvanomagnetic devices
    • H10N50/80—Constructional details
    • H10N50/85—Magnetic active materials

Definitions

  • the present invention relates to a magnetic sensor and a method for manufacturing a magnetic sensor.
  • a thin film magnet made of a hard magnetic film formed on a non-magnetic substrate, an insulating layer covering the thin film magnet, and uniaxial anisotropy formed on the insulating layer are provided.
  • a magneto-impedance effect element provided with one or a plurality of rectangular shaped soft magnetic material films as described above (see Patent Document 1).
  • a bias magnetic field is applied to this sensing element so that the impedance of the sensing element changes linearly with respect to a change in the external magnetic field.
  • a method for generating this bias magnetic field there is a method using a thin film magnet having magnetic anisotropy in the in-plane direction. The magnitude of the bias magnetic field applied to the sensing element by the thin film magnet is proportional to the residual magnetization of the hard magnetic material and the thickness of the hard magnetic material that form the thin film magnet.
  • the thickness of the hard magnetic material forming the thin-film magnet is simply increased in order to increase the bias magnetic field, the residual magnetization of the hard magnetic material is reduced, and the bias magnetic field applied to the sensing element by the thin-film magnet is increased. It will be difficult to do.
  • An object of the present invention is to increase the magnetic field applied to the sensing element by the thin film magnet, as compared with the case where the thin film magnet is composed of a single layer hard magnetic material.
  • a magnetic sensor to which the present invention is applied has two or more hard magnetic layers composed of a hard magnetic material containing Co and a non-magnetic material whose thickness is less than or equal to the thickness of the hard magnetic layer.
  • a non-magnetic layer is alternately laminated, is composed of a thin-film magnet having in-plane magnetic anisotropy and a soft magnetic material, and is arranged so as to face the thin-film magnet, and the longitudinal direction and the lateral direction are arranged.
  • a sensing element that has a uniaxial magnetic anisotropy in a direction that intersects the longitudinal direction while the longitudinal direction is directed to the magnetic field generated by the thin film magnet, and that senses the magnetic field by the magnetic impedance effect. Equipped with.
  • the hard magnetic layer of the thin film magnet is a hard magnetic layer containing at least one metal selected from Cr, Ta, Pt, Ru, Ni, W, B, V, and Cu in addition to Co. Can be configured.
  • the hard magnetic layer of the thin film magnet may be made of a hard magnetic material made of CoCrTa or CoCrNi.
  • the thin-film magnet can be characterized in that each of the hard magnetic layers has a thickness of 150 nm or less.
  • the thin-film magnet can be characterized in that a surface facing the sensing element is formed of the non-magnetic layer.
  • a method of manufacturing a magnetic sensor to which the present invention is applied includes a non-magnetic substrate, two or more hard magnetic layers made of a hard magnetic material containing Co, and a non-magnetic material.
  • the thin film magnet forming step may be characterized in that the hard magnetic layer and the non-magnetic layer are alternately laminated so that the non-magnetic layer is the uppermost layer.
  • the magnetic field applied to the sensing element by the thin film magnet can be increased as compared with the case where the thin film magnet is composed of a single layer hard magnetic material.
  • (A)-(b) is a figure explaining an example of the magnetic sensor to which this Embodiment is applied. It is a figure explaining the composition of the thin film magnet to which this embodiment is applied.
  • (A)-(b) is a figure explaining the relationship between the thickness of the hard magnetic material which comprises a thin film magnet, and the magnetic characteristic of a thin film magnet.
  • (A)-(d) is a figure explaining an example of the manufacturing method of a magnetic sensor.
  • (A)-(d) is a figure explaining an example of the manufacturing method of a magnetic sensor.
  • FIG. 1A and 1B are views for explaining an example of the magnetic sensor 1 to which the present embodiment is applied.
  • 1A is a plan view
  • FIG. 1B is a sectional view taken along line IB-IB in FIG.
  • a magnetic sensor 1 to which the present embodiment is applied includes a non-magnetic substrate 10 and a hard magnetic material (hard magnetic material layer 103a, which will be described later with reference to FIG. 2) provided on the substrate 10. And a non-magnetic material (non-magnetic material layer 103b, see FIG. 2 described later), and a soft magnetic material (soft magnetic material layer 105) that is laminated facing the thin-film magnet 20. And a sensing unit 30 that senses the magnetic field.
  • the cross-sectional structure of the magnetic sensor 1, particularly the cross-sectional structure of the thin film magnet 20, will be described later.
  • the hard magnetic material is a material with a large coercive force that retains the magnetized state even if the external magnetic field is removed when magnetized by the external magnetic field.
  • the soft magnetic material is a material having a small coercive force, which is easily magnetized by an external magnetic field but quickly returns to a state of no magnetization or a small magnetization when the external magnetic field is removed.
  • elements constituting the magnetic sensor 1 are represented by two-digit numbers, and layers processed into the elements (such as the hard magnetic layer 103a and the non-magnetic layer 103b) are indicated. Represented by numbers in the 100s. Then, for the number of the element, the number of the layer processed into the element is described in (). For example, in the case of the thin-film magnet 20, the thin-film magnet 20 (hard magnetic layer 103a, non-magnetic layer 103b) will be referred to. In the figure, it is written as 20 (103a, 103b). The same applies to other cases.
  • the magnetic sensor 1 has, for example, a quadrangular planar shape.
  • the sensing unit 30 and the yoke 40 formed on the uppermost part of the magnetic sensor 1 will be described.
  • the sensing unit 30 includes a plurality of sensing elements 31 each having a rectangular shape in a plan view having a longitudinal direction and a lateral direction, a connecting section 32 that connects adjacent sensing elements 31 in a zigzag manner, and an electric wire for supplying current. And a terminal portion 33 to which is connected.
  • four sensing elements 31 are arranged so that their longitudinal directions are parallel.
  • the sensing element 31 is a magneto-impedance effect element.
  • the sensitive element 31 has, for example, a length in the longitudinal direction of about 1 mm, a width in the lateral direction of several hundred ⁇ m, and a thickness (thickness of the soft magnetic layer 105) of 0.5 ⁇ m to 5 ⁇ m.
  • the distance between the adjacent sensing elements 31 is 50 ⁇ m to 150 ⁇ m.
  • the connecting portion 32 is provided between the end portions of the adjacent sensitive elements 31, and the adjacent sensitive elements 31 are connected in series in a zigzag manner.
  • the magnetic sensor 1 shown in FIG. 1A four sensing elements 31 are arranged in parallel, so that there are three connecting portions 32.
  • the number of sensing elements 31 is set according to the magnitude of the magnetic field to be sensed (measured). Therefore, for example, if the number of the sensitive elements 31 is two, the number of the connecting portions 32 is one. Moreover, if the number of the sensing elements 31 is one, the connecting portion 32 is not provided.
  • the width of the connecting portion 32 may be set according to the current flowing through the sensitive portion 30. For example, the width of the connecting portion 32 may be the same as that of the sensitive element 31.
  • the terminal portion 33 is provided at each of two end portions of the sensitive element 31 that are not connected by the connecting portion 32.
  • the terminal portion 33 includes a lead portion that pulls out from the sensing element 31, and a pad portion that connects an electric wire that supplies a current.
  • the lead-out portion is provided to provide two pad portions in the lateral direction of the sensitive element 31.
  • the pad portion may be provided so as to be continuous with the sensing element 31 without providing the lead portion.
  • the pad portion may have a size that can connect an electric wire. Since there are four sensing elements 31, the two terminal portions 33 are provided on the left side in FIG. When the number of the sensitive elements 31 is an odd number, the two terminal portions 33 may be provided separately on the left and right.
  • the sensitive element 31, the connecting portion 32, and the terminal portion 33 of the sensitive portion 30 are integrally configured by the single soft magnetic layer 105. Since the soft magnetic material layer 105 is conductive, it is possible to pass a current from one terminal portion 33 to the other terminal portion 33.
  • the above-mentioned numerical values such as the length and width of the sensing element 31 and the number of the sensing elements 31 arranged in parallel are examples, and may be changed depending on the value of the magnetic field to be sensed (measured), the soft magnetic material used, and the like.
  • the magnetic sensor 1 includes a yoke 40 that is provided so as to face the end of the sensing element 31 in the longitudinal direction.
  • a yoke 40 that is provided so as to face the end of the sensing element 31 in the longitudinal direction.
  • the yoke 40 guides a magnetic force line to the end of the sensing element 31 in the longitudinal direction. Therefore, the yoke 40 is made of a soft magnetic material (soft magnetic material layer 105) through which magnetic lines of force easily pass. That is, the sensing unit 30 and the yoke 40 are formed by the single soft magnetic layer 105.
  • the yoke 40 may not be provided when the magnetic force lines are sufficiently transmitted in the longitudinal direction of the sensing element 31.
  • the size of the magnetic sensor 1 is a few mm square in plan view.
  • the size of the magnetic sensor 1 may be another value.
  • the magnetic sensor 1 includes a non-magnetic substrate 10, a sensing layer including an adhesion layer 101, a control layer 102, a thin-film magnet 20 including a hard magnetic layer 103a and a non-magnetic layer 103b, an insulating layer 104, and a soft magnetic layer 105.
  • the part 30 and the yoke 40 are arranged (laminated) in this order.
  • the substrate 10 is a substrate made of a non-magnetic material, and examples thereof include oxide substrates such as glass and sapphire, semiconductor substrates such as silicon, and metal substrates such as aluminum, stainless steel, and nickel-phosphorus-plated metal.
  • the adhesion layer 101 is a layer for improving the adhesion of the control layer 102 to the substrate 10.
  • As the adhesion layer 101 it is preferable to use an alloy containing Cr or Ni. Examples of alloys containing Cr or Ni include CrTi, CrTa, and NiTa.
  • the adhesion layer 101 has a thickness of, for example, 5 nm to 50 nm. If there is no problem in the adhesion of the control layer 102 to the substrate 10, the adhesion layer 101 need not be provided. In this specification, the composition ratio of the alloy containing Cr or Ni is not shown. The same applies hereinafter.
  • the control layer 102 is a layer for controlling the magnetic anisotropy of the thin-film magnet 20 composed of the hard magnetic layer 103a and the non-magnetic layer 103b so that the magnetic anisotropy easily appears in the in-plane direction of the film.
  • the control layer 102 it is preferable to use Cr, Mo, or W or an alloy containing them (hereinafter, referred to as an alloy containing Cr or the like forming the control layer 102).
  • CrTi, CrMo, CrV, CrW, etc. are mentioned as an alloy containing Cr etc. which comprises the control layer 102.
  • the alloy containing Cr or the like that constitutes the control layer 102 has a bcc (body-centered cubic (body centered cubic lattice)) structure.
  • the thickness of the control layer 102 is, for example, 10 nm to 300 nm.
  • the thin film magnet 20 is configured by alternately stacking two or more hard magnetic layers 103a and non-magnetic layers 103b.
  • FIG. 2 is a diagram for explaining the configuration of the thin film magnet 20 to which the present embodiment is applied, and is an enlarged cross-sectional view around the thin film magnet 20 in the magnetic sensor 1 shown in FIG. 1B.
  • the thin-film magnet 20 is configured by alternately stacking four hard magnetic layers 103a and four non-magnetic layers 103b.
  • the total thickness of the thin-film magnet 20 including the two or more hard magnetic layers 103a and the non-magnetic layer 103b is, for example, 500 nm to 1500 nm.
  • the hard magnetic layer 103 a of the hard magnetic layer 103 a and the non-magnetic layer 103 b faces the control layer 102.
  • the lowermost layer of the thin film magnet 20 is composed of the hard magnetic layer 103a.
  • the uppermost layer of the thin film magnet 20 facing the insulating layer 104 is composed of the non-magnetic layer 103b.
  • the uppermost layer of the thin film magnet 20 may be composed of the hard magnetic layer 103a.
  • the thickness of each hard magnetic layer 103a is thicker than the thickness of each non-magnetic layer 103b.
  • the hard magnetic layer 103a forming the thin-film magnet 20 is an alloy containing Co as a main component and containing at least one metal selected from Cr, Ta, Pt, Ru, Ni, W, B, V, and Cu (hereinafter, It is preferable to use a Co alloy that constitutes the hard magnetic layer 103a.
  • CoCrTa, CoCrPt, CoCrNi, and CoCrPtB are preferably used as the Co alloy forming the hard magnetic layer 103a.
  • each hard magnetic layer 103a is preferably in the range of 5 nm to 150 nm.
  • the coercive force (Hc) and the squareness ratio (Mr / Ms) of the thin film magnet 20 are likely to decrease. In this case, the strength of the magnetic field applied to the sensing element 31 by the thin film magnet 20 may be reduced.
  • the total sum of the thicknesses of the plurality of hard magnetic layers 103a is, for example, in the range of 150 nm to 5000 nm, though it depends on the thickness of each hard magnetic layer 103a.
  • the hard magnetic layer 103a forming the thin-film magnet 20 has a hcp (hexagonal close-packed) structure that facilitates crystal growth on the control layer 102 made of an alloy containing Cr or the like having a bcc structure. Is good.
  • the hard magnetic layer 103a having the hcp structure is crystal-grown on the bcc structure, the c axis of the hcp structure is easily oriented so as to be in-plane. Therefore, the thin film magnet 20 including the hard magnetic layer 103a tends to have magnetic anisotropy in the in-plane direction.
  • the hard magnetic layer 103a is a polycrystal composed of aggregates having different crystal orientations, and each crystal has magnetic anisotropy in the in-plane direction. This magnetic anisotropy is derived from crystal magnetic anisotropy.
  • the substrate 10 may be heated to 100 ° C. to 600 ° C. in order to promote crystal growth of the alloy containing Cr or the like forming the control layer 102 and the Co alloy forming the hard magnetic layer 103a.
  • This heating facilitates crystal growth of the alloy containing Cr or the like forming the control layer 102 and facilitates crystal orientation of the hard magnetic layer 103a having the hcp structure so that the hard magnetic layer 103a has an in-plane easy magnetization axis. That is, magnetic anisotropy is easily imparted to the surface of the hard magnetic layer 103a.
  • the non-magnetic layer 103b forming the thin-film magnet 20 is a non-magnetic metal such as Cr, Ru, Ti, Mo, Pt, Cu, W, Mo (hereinafter referred to as a non-magnetic metal forming the non-magnetic layer 103b). )).
  • the nonmagnetic metal forming the nonmagnetic layer 103b is preferably Cr or Ru. Note that, among the plurality of nonmagnetic layers 103b, the nonmagnetic metals forming the respective nonmagnetic layers 103b may be the same or different from each other.
  • the thickness of the non-magnetic layer 103b is smaller than the thickness of the hard magnetic layer 103a and is in the range of 0.1 nm or more and 5 nm or less.
  • the thickness of the non-magnetic layer 103b is thicker than 5 nm, the interaction between the hard magnetic layers 103a facing each other via the non-magnetic layer 103b becomes weak, and the magnetic field applied to the sensing element 31 by the thin-film magnet 20. May decrease in strength.
  • the insulating layer 104 is made of a non-magnetic insulator and electrically insulates the thin film magnet 20 and the sensing unit 30 from each other.
  • the insulator forming the insulating layer 104 include oxides such as SiO 2 , Al 2 O 3 and TiO 2 , nitrides such as Si 3 N 4 and AlN.
  • the insulating layer 104 has a thickness of, for example, 0.01 ⁇ m to 50 ⁇ m.
  • the sensitive element 31 in the sensitive section 30 is provided with uniaxial magnetic anisotropy in a direction intersecting the longitudinal direction, for example, in a transverse direction (width direction) orthogonal to each other.
  • the soft magnetic material (soft magnetic material layer 105) forming the sensing element 31 is an amorphous alloy in which a refractory metal Nb, Ta, W, or the like is added to an alloy containing Co as a main component (hereinafter, the sensing element 31 is formed. It is preferable to use a Co alloy).
  • Examples of the Co alloy forming the sensitive element 31 include CoNbZr, CoFeTa, CoWZr, and the like.
  • the thickness of the soft magnetic material (soft magnetic material layer 105) forming the sensing element 31 is, for example, 0.5 ⁇ m to 5 ⁇ m.
  • the direction intersecting with the longitudinal direction may have an angle of more than 45 ° with respect to the longitudinal direction.
  • the adhesion layer 101, the control layer 102, the hard magnetic layer 103a, the non-magnetic layer 103b (thin film magnet 20), and the insulating layer 104 are processed so that the planar shape is a quadrangle (see FIG. 1A).
  • the thin-film magnet 20 has an N pole ((N) in FIG. 1B) and an S pole ((S) in FIG. 1B) on two opposing side surfaces of the exposed side surfaces.
  • the line connecting the N pole and the S pole of the thin film magnet 20 is oriented in the longitudinal direction of the sensing element 31 in the sensing section 30.
  • “toward the longitudinal direction” means that the angle formed by the line connecting the N pole and the S pole and the longitudinal direction is less than 45 °.
  • the angle formed by the line connecting the N pole and the S pole and the longitudinal direction is preferably as small as possible.
  • the magnetic force line emitted from the N pole of the thin-film magnet 20 once goes out of the magnetic sensor 1. Then, some of the magnetic lines of force pass through the sensing element 31 via the yoke 40a, and go out again via the yoke 40b. Then, the magnetic force line that has passed through the sensing element 31 returns to the S pole of the thin film magnet 20 together with the magnetic force line that does not pass through the sensing element 31. That is, the thin film magnet 20 applies a magnetic field in the longitudinal direction of the sensitive element 31.
  • the N pole and the S pole of the thin-film magnet 20 are collectively referred to as both magnetic poles, and when the N pole and the S pole are not distinguished, they are referred to as magnetic poles.
  • the yoke 40 (yokes 40a and 40b) is configured such that the shape viewed from the surface side of the substrate 10 becomes narrower as it approaches the sensing unit 30. This is for concentrating a magnetic field on the sensing unit 30 (collecting magnetic force lines). That is, the magnetic field in the sensing unit 30 is strengthened to further improve the sensitivity.
  • the width of the portion of the yoke 40 (yokes 40a and 40b) facing the sensing unit 30 does not have to be narrowed.
  • the distance between the yoke 40 (yokes 40a and 40b) and the sensing unit 30 may be, for example, 1 ⁇ m to 100 ⁇ m.
  • the magnetic characteristics of the thin-film magnet 20 change depending on the squareness ratio (Mr / Ms) of the hard magnetic material forming the thin-film magnet 20, the coercive force (Hc), the thickness (T) of the hard magnetic material, and the like.
  • Mr is the residual magnetization of the hard magnetic material
  • Ms is the saturation magnetization of the hard magnetic material.
  • the strength of the magnetic field applied to the sensing element 31 by the thin film magnet 20 is determined by the product (MrT) of the residual magnetization (Mr) and the thickness (T) of the hard magnetic material forming the thin film magnet 20. Proportional.
  • the thickness (T) of the hard magnetic material forming the thin-film magnet 20 is simply increased, the squareness ratio (Mr / Ms) of the hard magnetic material tends to decrease (see also FIG. 3A described later). reference).
  • the saturation magnetization (Ms) of the hard magnetic material takes a predetermined value depending on the type (material) of the hard magnetic material. Therefore, when the material of the hard magnetic material forming the thin film magnet 20 is the same, if the thickness (T) of the hard magnetic material forming the thin film magnet 20 is simply increased, the residual magnetization (Mr) of the hard magnetic material decreases. .
  • MrT does not increase, and the strength of the magnetic field applied to the sensing element 31 by the thin film magnet 20 increases. Is difficult to do.
  • the coercive force (Hc) tends to decrease (see also FIG. 3 (b) described later).
  • the coercive force (Hc) of the hard magnetic material forming the thin-film magnet 20 is low, the residual magnetization (Mr) of the thin-film magnet 20 is affected by the magnetic field (external magnetic field) around the magnetic sensor 1. There is a risk.
  • FIGS. 3A and 3B are diagrams for explaining the relationship between the thickness of the hard magnetic material (hard magnetic material layer 103 a) forming the thin film magnet 20 and the magnetic characteristics of the thin film magnet 20.
  • FIG. 3A shows the relationship between the thickness of the hard magnetic layer 103 a forming the thin film magnet 20 and the coercive force (Hc) of the thin film magnet 20.
  • FIG. 3B shows the relationship between the thickness of the hard magnetic layer 103 a forming the thin film magnet 20 and the squareness ratio (Mr / Ms) of the thin film magnet 20.
  • single layer indicates a case where the thin-film magnet 20 is composed of one hard magnetic material
  • “thickness” indicates this one hard magnetic material. It means the thickness of the body.
  • multilayer means that the thin-film magnet 20 is composed of two or more hard magnetic layers 103 a and non-magnetic layers 103 b alternately as in the present embodiment.
  • the “thickness” means the total thickness of the plurality of hard magnetic layers 103a forming the thin film magnet 20.
  • the body layers 103b are alternately laminated, and only the uppermost nonmagnetic layer 103b has a structure of Ru having a thickness of 1 nm.
  • the numbers attached to the “multilayer” graphs in FIGS. 3A and 3B indicate the number of hard magnetic layers 103 a constituting the thin film magnet 20.
  • the thin film magnet 20 when the thin film magnet 20 is composed of one layer of hard magnetic material (single layer), the coercive force (Hc) decreases as the thickness of the hard magnetic material increases. .
  • the thin-film magnet 20 has two or more hard magnetic layers 103a (multilayer), the number of hard magnetic layers 103a increases and the thickness of the hard magnetic layer (the thickness of the hard magnetic layer 103a) increases.
  • the total coercive force (Hc) is suppressed even when the total coercive force (Hc) is increased.
  • the thin-film magnet 20 when the thin-film magnet 20 is composed of one layer of hard magnetic material (single layer), the squareness ratio (Mr / Ms) increases as the thickness of the hard magnetic material increases. ) Is falling.
  • the thin-film magnet 20 has two or more hard magnetic layers 103a (multilayer), the number of hard magnetic layers 103a increases and the thickness of the hard magnetic layer (the thickness of the hard magnetic layer 103a) increases. Even if the total sum of the above, T) becomes thicker, the decrease of the squareness ratio (Mr / Ms) is suppressed.
  • the thin-film magnet 20 has a structure in which the hard magnetic layer 103a and the non-magnetic layer 103b, which are two or more layers, are alternately stacked, and thus the coercive force (Hc ) And the squareness ratio (Mr / Ms) are suppressed from decreasing, the thickness of the hard magnetic material (the total thickness of the hard magnetic material layer 103a, T) can be increased.
  • the product (MrT) of the residual magnetization (Mr) and the thickness (T) of the hard magnetic material forming the thin film magnet 20 can be increased, and the thin film magnet 20 can be made.
  • FIGS. 4A to 4D and FIGS. 5A to 5D are diagrams illustrating an example of a method of manufacturing the magnetic sensor 1.
  • 4A to 4D and FIGS. 5A to 5D show steps in the method of manufacturing the magnetic sensor 1. Note that FIGS. 4A to 4D and FIGS. 5A to 5D are representative steps, and may include other steps. Then, the process proceeds in the order of FIGS. 4A to 4D and FIGS. 5A to 5D.
  • FIGS. 4A to 4D and FIGS. 5A to 5D correspond to the cross-sectional views taken along the line IB-IB in FIG. 1A.
  • the substrate 10 is a substrate made of a non-magnetic material, for example, an oxide substrate such as glass or sapphire, a semiconductor substrate such as silicon, or a metal such as aluminum, stainless steel, or nickel-phosphorus plated metal. It is a metal substrate.
  • the substrate 10 may be provided with streak-shaped grooves or streak-shaped irregularities having a radius of curvature Ra of 0.1 nm to 100 nm, for example, by using a polishing machine or the like.
  • the direction of the streak-shaped groove or streak-shaped uneven line is provided in the direction connecting the N pole and the S pole of the thin-film magnet 20 constituted by the hard magnetic layer 103a and the nonmagnetic layer 103b. I hope you are there.
  • the easy axis of magnetization of the thin-film magnet 20 constituted by the hard magnetic layer 103a and the non-magnetic layer 103b is more likely to be oriented in the groove direction (the direction connecting the N pole and the S pole of the thin-film magnet 20). That is, the magnetization of the thin film magnet 20 is made easier.
  • the substrate 10 will be described as an example of glass having a diameter of about 95 mm and a thickness of about 0.5 mm.
  • a plurality of magnetic sensors 1 are collectively manufactured on the substrate 10 and then divided (cut) into individual magnetic sensors 1.
  • FIGS. 4A to 4D and FIGS. 5A to 5D one magnetic sensor 1 shown in the center is focused, but a part of the magnetic sensors 1 adjacent to the left and right is also shown together. The boundary between the adjacent magnetic sensors 1 is indicated by a chain line.
  • the adhesion layer 101 and the control layer 102 are sequentially formed (volume) on one surface (hereinafter referred to as the surface) of the substrate 10. .
  • the adhesion layer 101 which is an alloy containing Cr or Ni
  • the control layer 102 which is an alloy containing Cr or the like
  • This film formation can be performed by a sputtering method or the like.
  • the adhesion layer 101 and the control layer 102 are sequentially stacked on the substrate 10 by moving the substrate 10 so as to sequentially face the plurality of targets formed of the respective materials.
  • the substrate 10 may be heated to, for example, 100 ° C. to 600 ° C. in order to promote crystal growth.
  • the deposition of the adhesion layer 101 may or may not be performed on the substrate 10.
  • the substrate 10 may be heated before the adhesion layer 101 is formed in order to remove moisture or the like adsorbed on the surface of the substrate 10.
  • the Co alloy forming the hard magnetic layer 103a and the nonmagnetic metal forming the nonmagnetic layer 103b are formed. And are alternately formed a predetermined number of times.
  • This film formation can be performed by a sputtering method or the like.
  • the substrate 10 By moving the substrate 10 so as to alternately face the target formed of the material of the hard magnetic layer 103a and the target formed of the material of the nonmagnetic layer 103b, the hard magnetic layer is formed on the control layer 102.
  • the body layers 103a and the nonmagnetic layers 103b are alternately laminated.
  • the substrate 10 may be heated to, for example, 100 ° C. to 600 ° C. in order to promote crystal growth of the hard magnetic layer 103a.
  • the hard magnetic layer 103a and the nonmagnetic layer 103b are alternately formed.
  • the hard magnetic layer 103a and the nonmagnetic layer 103b are formed such that the nonmagnetic layer 103b is the uppermost layer. Accordingly, for example, when the substrate 10 is exposed to the outside of a sputtering device or the like after forming the hard magnetic layer 103a and the non-magnetic layer 103b and before forming the insulating layer 104, the hard magnetic layer 103a is formed. Is suppressed from being oxidized. When there is no risk of oxidation of the hard magnetic layer 103a, the hard magnetic layer 103a may be the uppermost layer without providing the non-magnetic layer 103b.
  • an insulating layer 104 made of an oxide such as SiO 2 , Al 2 O 3 or TiO 2 or a nitride such as Si 3 N 4 or AlN is formed ( accumulate.
  • the insulating layer 104 can be formed by a plasma CVD method, a reactive sputtering method, or the like.
  • a photoresist pattern (resist pattern) 111 having openings at portions where the sensitive portions 30 are formed and portions where the yoke 40 (yokes 40a and 40b) is formed is known. It is formed by the photolithography technology.
  • the soft magnetic layer 105 which is a Co alloy forming the sensing element 31, is formed (deposited).
  • the soft magnetic layer 105 can be formed by, for example, a sputtering method.
  • the resist pattern 111 is removed and the soft magnetic layer 105 on the resist pattern 111 is removed (lifted off).
  • the sensitive portion 30 and the yoke 40 are formed by the soft magnetic layer 105. That is, the sensing section 30 and the yoke 40 are formed by film-forming the soft magnetic layer 105 once.
  • the process of forming the sensitive portion 30 is called a sensitive portion forming process.
  • the susceptor forming step may include a step of forming the soft magnetic layer 105 and / or a step of forming the yoke 40.
  • uniaxial magnetic anisotropy is given to the soft magnetic layer 105 in the width direction of the sensing element 31 in the sensing section 30.
  • the uniaxial magnetic anisotropy is imparted to the soft magnetic layer 105 by heat treatment at 400 ° C. in a rotating magnetic field of 3 kG (0.3 T) (heat treatment in a rotating magnetic field) and subsequent 3 kG (0.3 T).
  • Heat treatment at 400 ° C. in a static magnetic field heat treatment in a static magnetic field.
  • the same uniaxial magnetic anisotropy is also given to the soft magnetic layer 105 that constitutes the yoke 40.
  • the yoke 40 only needs to play a role as a magnetic circuit, and may have uniaxial magnetic anisotropy.
  • the hard magnetic layer 103a constituting the thin film magnet 20 is magnetized.
  • the magnetization of the hard magnetic layer 103a can be performed by applying a magnetic field larger than the coercive force of the hard magnetic layer 103a in a static magnetic field or a pulsed magnetic field until the magnetization of the hard magnetic layer 103a is saturated.
  • the magnetic anisotropy is controlled in the in-plane direction in the steps of forming the hard magnetic layer 103a and the non-magnetic layer 103b that form the thin-film magnet 20 and the step of magnetizing the hard magnetic layer 103a. Since these are the steps for forming the thin film magnet 20 thus formed, they may be collectively referred to as a thin film magnet forming step.
  • the plurality of magnetic sensors 1 formed on the substrate 10 are divided (cut) into individual magnetic sensors 1. That is, as shown in the plan view of FIG. 1A, the substrate 10, the adhesion layer 101, the control layer 102, the hard magnetic layer 103a, the nonmagnetic layer 103b, and the insulating layer are formed so that the planar shape is a quadrangle. The 104 and the soft magnetic layer 105 are cut. Then, the magnetic poles (N pole and S pole) of the thin film magnet 20 are exposed on the side surfaces of the divided (cut) hard magnetic layer 103a and non-magnetic layer 103b. The hard magnetic layer 103a thus magnetized becomes the thin film magnet 20.
  • This division (cutting) can be performed by a dicing method, a laser cutting method, or the like.
  • the adhesion layer 101, the control layer 102, the hard magnetic material between the adjacent magnetic sensors 1 on the substrate 10 are formed.
  • the layer 103a, the nonmagnetic layer 103b, and the insulating layer 104 may be removed by etching so that the planar shape becomes a quadrangle (the planar shape of the magnetic sensor 1 shown in FIG. 1A). Then, the exposed substrate 10 may be divided (cut). After the step of forming the stacked body of FIGS.
  • the planar shape of the adhesion layer 101, the control layer 102, the hard magnetic layer 103a, the nonmagnetic layer 103b, and the insulating layer 104 is quadrangular. You may process so that it may become (planar shape of the magnetic sensor 1 shown to Fig.1 (a)).
  • the manufacturing method shown in FIGS. 4A to 4D and FIGS. 5A to 5D has a simplified process as compared with these manufacturing methods.
  • the magnetic sensor 1 is manufactured. Note that the uniaxial anisotropy is imparted to the soft magnetic layer 105 and / or the thin film magnet 20 is magnetized after the step of dividing the magnetic sensor 1 of FIG. You may perform it for every 1 or several magnetic sensor 1.
  • control layer 102 If the control layer 102 is not provided, it is necessary to impart in-plane magnetic anisotropy by depositing a plurality of hard magnetic layers 103a and then heating to 800 ° C. or higher to grow crystals. Becomes However, when the control layer 102 is provided as in the magnetic sensor 1 to which the first embodiment is applied, crystal growth is promoted by the control layer 102, so crystal growth at a high temperature of 800 ° C. or higher is performed. Does not need
  • the uniaxial anisotropy is imparted to the sensing element 31 of the sensing section 30, instead of performing the heat treatment in the rotating magnetic field and the heat treatment in the static magnetic field as described above, the soft magnetic layer 105 which is a Co alloy constituting the sensing element 31. It may be performed by using a magnetron sputtering method at the time of depositing. In the magnetron sputtering method, a magnetic field is formed using a magnet, and the electrons generated by the discharge are confined (concentrated) on the surface of the target. This increases the probability of collision between electrons and gas, promotes ionization of gas, and improves the deposition rate (deposition rate) of the film.
  • a uniaxial anisotropy is imparted to the soft magnetic material layer 105 at the same time as the soft magnetic material layer 105 is deposited by a magnetic field formed by a magnet used in the magnetron sputtering method. This makes it possible to omit the step of imparting uniaxial anisotropy in the heat treatment in the rotating magnetic field and the heat treatment in the static magnetic field.
  • SYMBOLS 1 Magnetic sensor, 10 ... Substrate, 20 ... Thin film magnet, 30 ... Sensing part, 31 ... Sensing element, 32 ... Connection part, 33 ... Terminal part, 40, 40a, 40b ... Yoke, 101 ... Adhesion layer, 102 ... Control Layer, 103a ... Hard magnetic layer, 103b ... Nonmagnetic layer, 104 ... Insulating layer, 105 ... Soft magnetic layer

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Abstract

This magnetic sensor comprises: a thin-film magnet 20 in which two or more hard-magnetic-body layers 103a each configured from a hard magnetic body that includes Co, and a non-magnetic-body layer 103b that is configured from a non-magnetic body and has a thickness equal to or less than that of the hard-magnetic-body layers 103a, are arranged in an alternating manner, the thin-film magnet 20 having magnetic anisotropy in an in-plane direction; and a sensing element that is configured from a soft magnetic body and is arranged facing the thin-film magnet 20, the sensing element having a long-axis direction and a short-axis direction, the long-axis direction being oriented in the direction of a magnetic field generated by the thin-film magnet 20 and having axial magnetic anisotropy in the direction intersecting the long-axis direction, and the sensing element sensing the magnetic field using a magnetic impedance effect.

Description

磁気センサおよび磁気センサの製造方法Magnetic sensor and method of manufacturing magnetic sensor
　本発明は、磁気センサおよび磁気センサの製造方法に関する。 The present invention relates to a magnetic sensor and a method for manufacturing a magnetic sensor.
　公報記載の従来技術として、非磁性基板上に形成された硬磁性体膜からなる薄膜磁石と、前記薄膜磁石の上を覆う絶縁層と、前記絶縁層上に形成された一軸異方性を付与された一個または複数個の長方形状の軟磁性体膜からなる感磁部とを備えた磁気インピーダンス効果素子が存在する（特許文献１参照）。 As the prior art described in the publication, a thin film magnet made of a hard magnetic film formed on a non-magnetic substrate, an insulating layer covering the thin film magnet, and uniaxial anisotropy formed on the insulating layer are provided. There is a magneto-impedance effect element provided with one or a plurality of rectangular shaped soft magnetic material films as described above (see Patent Document 1).
特開２００８－２４９４０６号公報JP, 2008-249406, A
　ところで、磁気インピーダンス効果により磁界を感受する感受素子を用いた磁気センサでは、この感受素子にバイアス磁界をかけて、感受素子のインピーダンスが外部磁場の変化に対して直線的に変化するようにする。このバイアス磁界を生成するための方法として、面内方向に磁気異方性を有する薄膜磁石を用いる方法がある。
　薄膜磁石により感受素子に印加されるバイアス磁界の大きさは、薄膜磁石を構成する硬磁性体の残留磁化および硬磁性体の厚さに比例する。しかしながら、バイアス磁界を大きくしようとして薄膜磁石を構成する硬磁性体の厚さを単純に厚くすると、硬磁性体の残留磁化が低下してしまい、薄膜磁石により感受素子に印加されるバイアス磁界を大きくすることは難しくなる。 By the way, in a magnetic sensor using a sensing element that senses a magnetic field by the magnetic impedance effect, a bias magnetic field is applied to this sensing element so that the impedance of the sensing element changes linearly with respect to a change in the external magnetic field. As a method for generating this bias magnetic field, there is a method using a thin film magnet having magnetic anisotropy in the in-plane direction.
The magnitude of the bias magnetic field applied to the sensing element by the thin film magnet is proportional to the residual magnetization of the hard magnetic material and the thickness of the hard magnetic material that form the thin film magnet. However, if the thickness of the hard magnetic material forming the thin-film magnet is simply increased in order to increase the bias magnetic field, the residual magnetization of the hard magnetic material is reduced, and the bias magnetic field applied to the sensing element by the thin-film magnet is increased. It will be difficult to do.
　本発明は、薄膜磁石を単層の硬磁性体により構成する場合と比べ、薄膜磁石によって感受素子に印加される磁界を大きくすることを目的とする。 An object of the present invention is to increase the magnetic field applied to the sensing element by the thin film magnet, as compared with the case where the thin film magnet is composed of a single layer hard magnetic material.
　本発明が適用される磁気センサは、Ｃｏを含む硬磁性体で構成される２層以上の硬磁性体層と、非磁性体で構成され厚さが当該硬磁性体層の厚さ以下である非磁性体層とが交互に積層され、面内方向に磁気異方性を有する薄膜磁石と、軟磁性体で構成されるとともに、前記薄膜磁石に対向して配置され、長手方向と短手方向とを有し、当該長手方向が当該薄膜磁石の発生する磁界の方向を向くとともに、当該長手方向と交差する方向に一軸磁気異方性を有し、磁気インピーダンス効果により磁界を感受する感受素子とを備える。
　ここで、前記薄膜磁石の前記硬磁性体層は、Ｃｏに加えて、Ｃｒ、Ｔａ、Ｐｔ、Ｒｕ、Ｎｉ、Ｗ、Ｂ、Ｖ、Ｃｕから選択される少なくとも１つの金属を含む硬磁性体で構成されることを特徴とすることができる。
　また、前記薄膜磁石の前記硬磁性体層は、ＣｏＣｒＴａまたはＣｏＣｒＮｉからなる硬磁性体で構成されることを特徴とすることができる。
　さらに、前記薄膜磁石は、それぞれの前記硬磁性体層の厚さが１５０ｎｍ以下であることを特徴とすることができる。
　さらにまた、前記薄膜磁石は、前記感受素子に対向する面が前記非磁性体層により構成されていることを特徴とすることができる。 A magnetic sensor to which the present invention is applied has two or more hard magnetic layers composed of a hard magnetic material containing Co and a non-magnetic material whose thickness is less than or equal to the thickness of the hard magnetic layer. A non-magnetic layer is alternately laminated, is composed of a thin-film magnet having in-plane magnetic anisotropy and a soft magnetic material, and is arranged so as to face the thin-film magnet, and the longitudinal direction and the lateral direction are arranged. And a sensing element that has a uniaxial magnetic anisotropy in a direction that intersects the longitudinal direction while the longitudinal direction is directed to the magnetic field generated by the thin film magnet, and that senses the magnetic field by the magnetic impedance effect. Equipped with.
Here, the hard magnetic layer of the thin film magnet is a hard magnetic layer containing at least one metal selected from Cr, Ta, Pt, Ru, Ni, W, B, V, and Cu in addition to Co. Can be configured.
The hard magnetic layer of the thin film magnet may be made of a hard magnetic material made of CoCrTa or CoCrNi.
Further, the thin-film magnet can be characterized in that each of the hard magnetic layers has a thickness of 150 nm or less.
Furthermore, the thin-film magnet can be characterized in that a surface facing the sensing element is formed of the non-magnetic layer.
　また、他の観点から捉えると、本発明が適用される磁気センサの製造方法は、非磁性の基板上に、Ｃｏを含む硬磁性体からなる２層以上の硬磁性体層と、非磁性体からなる非磁性体層とを交互に積層して、磁気異方性が面内方向に制御された薄膜磁石を形成する薄膜磁石形成工程と、前記薄膜磁石の発生する磁束が透過する方向と交差する方向に一軸磁気異方性を有する感受素子を備える感受部を形成する感受部形成工程と、を含む。
　ここで、前記薄膜磁石形成工程は、前記非磁性体層が最上層となるように、前記硬磁性体層と当該非磁性体層とを交互に積層することを特徴とすることができる。 From another point of view, a method of manufacturing a magnetic sensor to which the present invention is applied includes a non-magnetic substrate, two or more hard magnetic layers made of a hard magnetic material containing Co, and a non-magnetic material. The thin-film magnet forming step of forming a thin-film magnet whose magnetic anisotropy is controlled in the in-plane direction by alternately laminating a non-magnetic layer made of Forming a sensitive portion including a sensitive element having uniaxial magnetic anisotropy in the direction.
Here, the thin film magnet forming step may be characterized in that the hard magnetic layer and the non-magnetic layer are alternately laminated so that the non-magnetic layer is the uppermost layer.
　本発明によれば、薄膜磁石を単層の硬磁性体により構成する場合と比べ、薄膜磁石によって感受素子に印加される磁界を大きくすることができる。 According to the present invention, the magnetic field applied to the sensing element by the thin film magnet can be increased as compared with the case where the thin film magnet is composed of a single layer hard magnetic material.
（ａ）～（ｂ）は、本実施の形態が適用される磁気センサの一例を説明する図である。(A)-(b) is a figure explaining an example of the magnetic sensor to which this Embodiment is applied. 本実施の形態が適用される薄膜磁石の構成を説明する図である。It is a figure explaining the composition of the thin film magnet to which this embodiment is applied. （ａ）～（ｂ）は、薄膜磁石を構成する硬磁性体の厚さと、薄膜磁石の磁気特性との関係を説明する図である。(A)-(b) is a figure explaining the relationship between the thickness of the hard magnetic material which comprises a thin film magnet, and the magnetic characteristic of a thin film magnet. （ａ）～（ｄ）は、磁気センサの製造方法の一例を説明する図である。(A)-(d) is a figure explaining an example of the manufacturing method of a magnetic sensor. （ａ）～（ｄ）は、磁気センサの製造方法の一例を説明する図である。(A)-(d) is a figure explaining an example of the manufacturing method of a magnetic sensor.
　本明細書で説明する磁気センサは、いわゆる磁気インピーダンス効果素子を用いたものである。
　以下、添付図面を参照して、本発明の実施の形態について詳細に説明する。 The magnetic sensor described in this specification uses a so-called magneto-impedance effect element.
Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.
［磁気センサ１］
　図１（ａ）～（ｂ）は、本実施の形態が適用される磁気センサ１の一例を説明する図である。図１（ａ）は、平面図、図１（ｂ）は、図１（ａ）におけるＩＢ－ＩＢ線での断面図である。
　図１（ｂ）に示すように、本実施の形態が適用される磁気センサ１は、非磁性の基板１０と、基板１０上に設けられ硬磁性体（硬磁性体層１０３ａ、後述する図２参照）および非磁性体（非磁性体層１０３ｂ、後述する図２参照）で構成された薄膜磁石２０と、薄膜磁石２０に対向して積層され、軟磁性体（軟磁性体層１０５）で構成されて磁場を感受する感受部３０とを備える。なお、磁気センサ１の断面構造、特に薄膜磁石２０の断面構造については、後に詳述する。 [Magnetic sensor 1]
1A and 1B are views for explaining an example of the magnetic sensor 1 to which the present embodiment is applied. 1A is a plan view, and FIG. 1B is a sectional view taken along line IB-IB in FIG.
As shown in FIG. 1B, a magnetic sensor 1 to which the present embodiment is applied includes a non-magnetic substrate 10 and a hard magnetic material (hard magnetic material layer 103a, which will be described later with reference to FIG. 2) provided on the substrate 10. And a non-magnetic material (non-magnetic material layer 103b, see FIG. 2 described later), and a soft magnetic material (soft magnetic material layer 105) that is laminated facing the thin-film magnet 20. And a sensing unit 30 that senses the magnetic field. The cross-sectional structure of the magnetic sensor 1, particularly the cross-sectional structure of the thin film magnet 20, will be described later.
　ここで硬磁性体とは、外部磁界によって磁化されると、外部磁界を取り除いても磁化された状態が保持される、いわゆる保磁力の大きい材料である。一方、軟磁性体とは、外部磁界によって容易に磁化されるが、外部磁界を取り除くと速やかに磁化がないか又は磁化が小さい状態に戻る、いわゆる保磁力の小さい材料である。 Here, the hard magnetic material is a material with a large coercive force that retains the magnetized state even if the external magnetic field is removed when magnetized by the external magnetic field. On the other hand, the soft magnetic material is a material having a small coercive force, which is easily magnetized by an external magnetic field but quickly returns to a state of no magnetization or a small magnetization when the external magnetic field is removed.
　なお、本明細書においては、磁気センサ１を構成する要素（薄膜磁石２０など）を二桁の数字で表し、要素に加工される層（硬磁性体層１０３ａ、非磁性体層１０３ｂなど）を１００番台の数字で表す。そして、要素の数字に対して、要素に加工される層の番号を（　）内に表記する。例えば薄膜磁石２０の場合、薄膜磁石２０（硬磁性体層１０３ａ、非磁性体層１０３ｂ）と表記する。図においては、２０（１０３ａ，１０３ｂ）と表記する。他の場合も同様である。 In the present specification, elements constituting the magnetic sensor 1 (such as the thin-film magnet 20) are represented by two-digit numbers, and layers processed into the elements (such as the hard magnetic layer 103a and the non-magnetic layer 103b) are indicated. Represented by numbers in the 100s. Then, for the number of the element, the number of the layer processed into the element is described in (). For example, in the case of the thin-film magnet 20, the thin-film magnet 20 (hard magnetic layer 103a, non-magnetic layer 103b) will be referred to. In the figure, it is written as 20 (103a, 103b). The same applies to other cases.
　図１（ａ）により、磁気センサ１の平面構造を説明する。磁気センサ１は、一例として四角形の平面形状を有する。ここでは、磁気センサ１の最上部に形成された感受部３０及びヨーク４０を説明する。感受部３０は、平面形状が長手方向と短手方向とを有する短冊状である複数の感受素子３１と、隣接する感受素子３１をつづら折りに直列接続する接続部３２と、電流供給のための電線が接続される端子部３３とを備える。ここでは、４個の感受素子３１が、長手方向が並列するように配置されている。また、本実施の形態の磁気センサ１では、感受素子３１が、磁気インピーダンス効果素子である。
　感受素子３１は、例えば長手方向の長さが約１ｍｍ、短手方向の幅が数１００μｍ、厚さ（軟磁性体層１０５の厚さ）が０．５μｍ～５μｍである。隣接する感受素子３１間の間隔は、５０μｍ～１５０μｍである。 A planar structure of the magnetic sensor 1 will be described with reference to FIG. The magnetic sensor 1 has, for example, a quadrangular planar shape. Here, the sensing unit 30 and the yoke 40 formed on the uppermost part of the magnetic sensor 1 will be described. The sensing unit 30 includes a plurality of sensing elements 31 each having a rectangular shape in a plan view having a longitudinal direction and a lateral direction, a connecting section 32 that connects adjacent sensing elements 31 in a zigzag manner, and an electric wire for supplying current. And a terminal portion 33 to which is connected. Here, four sensing elements 31 are arranged so that their longitudinal directions are parallel. Moreover, in the magnetic sensor 1 of the present embodiment, the sensing element 31 is a magneto-impedance effect element.
The sensitive element 31 has, for example, a length in the longitudinal direction of about 1 mm, a width in the lateral direction of several hundred μm, and a thickness (thickness of the soft magnetic layer 105) of 0.5 μm to 5 μm. The distance between the adjacent sensing elements 31 is 50 μm to 150 μm.
　接続部３２は、隣接する感受素子３１の端部間に設けられ、隣接する感受素子３１をつづら折りに直列接続する。図１（ａ）に示す磁気センサ１では、４個の感受素子３１が並列に配置されているため、接続部３２は３個ある。感受素子３１の数は、感受（計測）したい磁界の大きさなどによって設定される。よって、例えば感受素子３１が２個であれば、接続部３２は１個である。また、感受素子３１が１個であれば、接続部３２を備えない。なお、接続部３２の幅は、感受部３０に流す電流によって設定すればよい。例えば、接続部３２の幅は、感受素子３１と同じであってもよい。 The connecting portion 32 is provided between the end portions of the adjacent sensitive elements 31, and the adjacent sensitive elements 31 are connected in series in a zigzag manner. In the magnetic sensor 1 shown in FIG. 1A, four sensing elements 31 are arranged in parallel, so that there are three connecting portions 32. The number of sensing elements 31 is set according to the magnitude of the magnetic field to be sensed (measured). Therefore, for example, if the number of the sensitive elements 31 is two, the number of the connecting portions 32 is one. Moreover, if the number of the sensing elements 31 is one, the connecting portion 32 is not provided. The width of the connecting portion 32 may be set according to the current flowing through the sensitive portion 30. For example, the width of the connecting portion 32 may be the same as that of the sensitive element 31.
　端子部３３は、接続部３２で接続されていない感受素子３１の２個の端部にそれぞれ設けられている。端子部３３は、感受素子３１から引き出す引き出し部と、電流を供給する電線を接続するパッド部とを備える。引き出し部は、２個のパッド部を感受素子３１の短手方向に設けるために備えられている。引き出し部を設けずパッド部を感受素子３１に連続するように設けてもよい。パッド部は、電線を接続しうる大きさであればよい。なお、感受素子３１が４個であるため、２個の端子部３３は図１（ａ）において左側に設けられている。感受素子３１の数が奇数の場合には、２個の端子部３３を左右に分けて設ければよい。 The terminal portion 33 is provided at each of two end portions of the sensitive element 31 that are not connected by the connecting portion 32. The terminal portion 33 includes a lead portion that pulls out from the sensing element 31, and a pad portion that connects an electric wire that supplies a current. The lead-out portion is provided to provide two pad portions in the lateral direction of the sensitive element 31. The pad portion may be provided so as to be continuous with the sensing element 31 without providing the lead portion. The pad portion may have a size that can connect an electric wire. Since there are four sensing elements 31, the two terminal portions 33 are provided on the left side in FIG. When the number of the sensitive elements 31 is an odd number, the two terminal portions 33 may be provided separately on the left and right.
　そして、感受部３０の感受素子３１、接続部３２及び端子部３３は、一層の軟磁性体層１０５で一体に構成されている。軟磁性体層１０５は、導電性であるので、一方の端子部３３から他方の端子部３３に、電流を流すことができる。
　なお、感受素子３１の長さ及び幅、並列させる個数など上記した数値は一例であって、感受（計測）する磁界の値や用いる軟磁性体材料などによって変更してもよい。 The sensitive element 31, the connecting portion 32, and the terminal portion 33 of the sensitive portion 30 are integrally configured by the single soft magnetic layer 105. Since the soft magnetic material layer 105 is conductive, it is possible to pass a current from one terminal portion 33 to the other terminal portion 33.
The above-mentioned numerical values such as the length and width of the sensing element 31 and the number of the sensing elements 31 arranged in parallel are examples, and may be changed depending on the value of the magnetic field to be sensed (measured), the soft magnetic material used, and the like.
　さらに、磁気センサ１は、感受素子３１の長手方向の端部に対向して設けられたヨーク４０を備える。ここでは、感受素子３１の長手方向の両端部に対向してそれぞれが設けられた２個のヨーク４０ａ、４０ｂを備える。なお、ヨーク４０ａ、４０ｂをそれぞれ区別しない場合は、ヨーク４０と表記する。ヨーク４０は、感受素子３１の長手方向の端部に磁力線を誘導する。このため、ヨーク４０は、磁力線が透過しやすい軟磁性体（軟磁性体層１０５）で構成されている。つまり、感受部３０及びヨーク４０は、一層の軟磁性体層１０５により形成されている。なお、感受素子３１の長手方向に磁力線が十分透過する場合には、ヨーク４０を備えなくてもよい。 Further, the magnetic sensor 1 includes a yoke 40 that is provided so as to face the end of the sensing element 31 in the longitudinal direction. Here, it is provided with two yokes 40a and 40b, which are provided so as to face both ends in the longitudinal direction of the sensing element 31, respectively. When the yokes 40a and 40b are not distinguished from each other, they are referred to as the yoke 40. The yoke 40 guides a magnetic force line to the end of the sensing element 31 in the longitudinal direction. Therefore, the yoke 40 is made of a soft magnetic material (soft magnetic material layer 105) through which magnetic lines of force easily pass. That is, the sensing unit 30 and the yoke 40 are formed by the single soft magnetic layer 105. The yoke 40 may not be provided when the magnetic force lines are sufficiently transmitted in the longitudinal direction of the sensing element 31.
　以上のことから、磁気センサ１の大きさは、平面形状において数ｍｍ角である。なお、磁気センサ１の大きさは、他の値であってもよい。 From the above, the size of the magnetic sensor 1 is a few mm square in plan view. The size of the magnetic sensor 1 may be another value.
　次に、図１（ｂ）により、磁気センサ１の断面構造を詳述する。磁気センサ１は、非磁性の基板１０上に、密着層１０１、制御層１０２、硬磁性体層１０３ａ及び非磁性体層１０３ｂからなる薄膜磁石２０、絶縁層１０４、軟磁性体層１０５からなる感受部３０及びヨーク４０がこの順に配置（積層）されて構成されている。 Next, the sectional structure of the magnetic sensor 1 will be described in detail with reference to FIG. The magnetic sensor 1 includes a non-magnetic substrate 10, a sensing layer including an adhesion layer 101, a control layer 102, a thin-film magnet 20 including a hard magnetic layer 103a and a non-magnetic layer 103b, an insulating layer 104, and a soft magnetic layer 105. The part 30 and the yoke 40 are arranged (laminated) in this order.
　基板１０は、非磁性体からなる基板であって、例えばガラス、サファイアといった酸化物基板やシリコンなどの半導体基板、あるいは、アルミニウム、ステンレススティール、ニッケルリンメッキを施した金属等の金属基板等が挙げられる。
　密着層１０１は、基板１０に対する制御層１０２の密着性を向上させるための層である。密着層１０１としては、Ｃｒ又はＮｉを含む合金を用いるのがよい。Ｃｒ又はＮｉを含む合金としては、ＣｒＴｉ、ＣｒＴａ、ＮｉＴａなどが挙げられる。密着層１０１の厚さは、例えば５ｎｍ～５０ｎｍである。なお、基板１０に対する制御層１０２の密着性に問題がなければ、密着層１０１を設けることを要しない。なお、本明細書においては、Ｃｒ又はＮｉを含む合金の組成比を示さない。以下同様である。 The substrate 10 is a substrate made of a non-magnetic material, and examples thereof include oxide substrates such as glass and sapphire, semiconductor substrates such as silicon, and metal substrates such as aluminum, stainless steel, and nickel-phosphorus-plated metal. To be
The adhesion layer 101 is a layer for improving the adhesion of the control layer 102 to the substrate 10. As the adhesion layer 101, it is preferable to use an alloy containing Cr or Ni. Examples of alloys containing Cr or Ni include CrTi, CrTa, and NiTa. The adhesion layer 101 has a thickness of, for example, 5 nm to 50 nm. If there is no problem in the adhesion of the control layer 102 to the substrate 10, the adhesion layer 101 need not be provided. In this specification, the composition ratio of the alloy containing Cr or Ni is not shown. The same applies hereinafter.
　制御層１０２は、硬磁性体層１０３ａおよび非磁性体層１０３ｂで構成される薄膜磁石２０の磁気異方性が膜の面内方向に発現しやすいように制御する層である。制御層１０２としては、Ｃｒ、Ｍｏ若しくはＷ又はそれらを含む合金（以下では、制御層１０２を構成するＣｒ等を含む合金と表記する。）を用いるのがよい。制御層１０２を構成するＣｒ等を含む合金としては、ＣｒＴｉ、ＣｒＭｏ、ＣｒＶ、ＣｒＷ等が挙げられる。また、制御層１０２を構成するＣｒ等を含む合金は、ｂｃｃ（body-centered cubic（体心立方格子））構造を有する。制御層１０２の厚さは、例えば１０ｎｍ～３００ｎｍである。 The control layer 102 is a layer for controlling the magnetic anisotropy of the thin-film magnet 20 composed of the hard magnetic layer 103a and the non-magnetic layer 103b so that the magnetic anisotropy easily appears in the in-plane direction of the film. As the control layer 102, it is preferable to use Cr, Mo, or W or an alloy containing them (hereinafter, referred to as an alloy containing Cr or the like forming the control layer 102). CrTi, CrMo, CrV, CrW, etc. are mentioned as an alloy containing Cr etc. which comprises the control layer 102. Further, the alloy containing Cr or the like that constitutes the control layer 102 has a bcc (body-centered cubic (body centered cubic lattice)) structure. The thickness of the control layer 102 is, for example, 10 nm to 300 nm.
　薄膜磁石２０は、二層以上の硬磁性体層１０３ａと、非磁性体層１０３ｂとが交互に積層されて構成される。図２は、本実施の形態が適用される薄膜磁石２０の構成を説明する図であって、図１（ｂ）に示した磁気センサ１における薄膜磁石２０の周囲の拡大断面図である。
　図２に示す例では、薄膜磁石２０は、４層の硬磁性体層１０３ａと、４層の非磁性体層１０３ｂとが交互に積層されて構成されている。二層以上の硬磁性体層１０３ａと、非磁性体層１０３ｂとにより構成される薄膜磁石２０全体の厚さは、例えば５００ｎｍ～１５００ｎｍである。 The thin film magnet 20 is configured by alternately stacking two or more hard magnetic layers 103a and non-magnetic layers 103b. FIG. 2 is a diagram for explaining the configuration of the thin film magnet 20 to which the present embodiment is applied, and is an enlarged cross-sectional view around the thin film magnet 20 in the magnetic sensor 1 shown in FIG. 1B.
In the example shown in FIG. 2, the thin-film magnet 20 is configured by alternately stacking four hard magnetic layers 103a and four non-magnetic layers 103b. The total thickness of the thin-film magnet 20 including the two or more hard magnetic layers 103a and the non-magnetic layer 103b is, for example, 500 nm to 1500 nm.
　また、図２に示すように、薄膜磁石２０は、硬磁性体層１０３ａと非磁性体層１０３ｂとのうち、硬磁性体層１０３ａが制御層１０２に対向するようになっている。言い換えると、薄膜磁石２０の最下層は、硬磁性体層１０３ａにより構成されている。一方、絶縁層１０４に対向する薄膜磁石２０の最上層は、非磁性体層１０３ｂにより構成されている。なお、薄膜磁石２０の最上層は、硬磁性体層１０３ａにより構成されていてもよい。
　さらに、図２に示すように、薄膜磁石２０は、それぞれの硬磁性体層１０３ａの厚さが、それぞれの非磁性体層１０３ｂの厚さと比べて厚い。 Further, as shown in FIG. 2, in the thin film magnet 20, the hard magnetic layer 103 a of the hard magnetic layer 103 a and the non-magnetic layer 103 b faces the control layer 102. In other words, the lowermost layer of the thin film magnet 20 is composed of the hard magnetic layer 103a. On the other hand, the uppermost layer of the thin film magnet 20 facing the insulating layer 104 is composed of the non-magnetic layer 103b. The uppermost layer of the thin film magnet 20 may be composed of the hard magnetic layer 103a.
Further, as shown in FIG. 2, in the thin-film magnet 20, the thickness of each hard magnetic layer 103a is thicker than the thickness of each non-magnetic layer 103b.
　薄膜磁石２０を構成する硬磁性体層１０３ａは、Ｃｏを主成分とし、Ｃｒ、Ｔａ、Ｐｔ、Ｒｕ、Ｎｉ、Ｗ、Ｂ、Ｖ、Ｃｕから選ばれる少なくとも１つの金属を含む合金（以下では、硬磁性体層１０３ａを構成するＣｏ合金と表記する。）を用いることがよい。硬磁性体層１０３ａを構成するＣｏ合金として具体的には、Ｃｏ－Ｍ1（Ｍ1＝Ｃｒ、Ｔａ、Ｐｔ、Ｒｕ、Ｎｉ、Ｗ、Ｂ、Ｖ、Ｃｕ）、ＣｏＣｒ－Ｍ2（Ｍ2＝Ｔａ、Ｐｔ、Ｒｕ、Ｎｉ、Ｗ、Ｂ、Ｖ、Ｃｕ）、ＣｏＣｒＴａ－Ｍ3（Ｍ3＝Ｐｔ、Ｒｕ、Ｎｉ、Ｗ、Ｂ、Ｖ、Ｃｕ）、ＣｏＣｒＰｔ－Ｍ4（Ｍ4＝Ｒｕ、Ｎｉ、Ｗ、Ｂ、Ｖ、Ｃｕ）を用いることがよい。硬磁性体層１０３ａを構成するＣｏ合金としては、これらの中でも、ＣｏＣｒＴａ、ＣｏＣｒＰｔ、ＣｏＣｒＮｉ、ＣｏＣｒＰｔＢを用いることが好ましい。 The hard magnetic layer 103a forming the thin-film magnet 20 is an alloy containing Co as a main component and containing at least one metal selected from Cr, Ta, Pt, Ru, Ni, W, B, V, and Cu (hereinafter, It is preferable to use a Co alloy that constitutes the hard magnetic layer 103a. Specific examples of the Co alloy forming the hard magnetic layer 103a include Co—M 1 (M 1 = Cr, Ta, Pt, Ru, Ni, W, B, V, Cu), CoCr—M 2 (M 2 = Ta, Pt, Ru, Ni, W, B, V, Cu), CoCrTa-M 3 (M 3 = Pt, Ru, Ni, W, B, V, Cu), CoCrPt-M 4 (M 4 = Ru) , Ni, W, B, V, Cu) is preferably used. Among these, CoCrTa, CoCrPt, CoCrNi, and CoCrPtB are preferably used as the Co alloy forming the hard magnetic layer 103a.
　それぞれの硬磁性体層１０３ａの厚さは、５ｎｍ以上１５０ｎｍ以下の範囲であることが好ましい。それぞれの硬磁性体層１０３ａの厚さが１５０ｎｍを超える場合、薄膜磁石２０の保磁力（Ｈｃ）や角型比（Ｍｒ／Ｍｓ）が低下しやすくなる。この場合、薄膜磁石２０により感受素子３１に印加される磁界の強さが低下するおそれがある。
　また、複数の硬磁性体層１０３ａの厚さを足した総和は、それぞれの硬磁性体層１０３ａの厚さにもよるが、例えば１５０ｎｍ以上５０００ｎｍ以下の範囲である。 The thickness of each hard magnetic layer 103a is preferably in the range of 5 nm to 150 nm. When the thickness of each hard magnetic layer 103a exceeds 150 nm, the coercive force (Hc) and the squareness ratio (Mr / Ms) of the thin film magnet 20 are likely to decrease. In this case, the strength of the magnetic field applied to the sensing element 31 by the thin film magnet 20 may be reduced.
The total sum of the thicknesses of the plurality of hard magnetic layers 103a is, for example, in the range of 150 nm to 5000 nm, though it depends on the thickness of each hard magnetic layer 103a.
　上述したように、制御層１０２を構成するＣｒ等を含む合金は、ｂｃｃ構造を有する。よって、薄膜磁石２０を構成する硬磁性体層１０３ａは、ｂｃｃ構造のＣｒ等を含む合金で構成された制御層１０２上において結晶成長しやすいｈｃｐ（hexagonal close-packed（六方最密充填））構造であるとよい。ｂｃｃ構造上にｈｃｐ構造の硬磁性体層１０３ａを結晶成長させると、ｈｃｐ構造のｃ軸が面内に向くように配向しやすい。よって、硬磁性体層１０３ａを含む薄膜磁石２０が面内方向に磁気異方性を有するようになりやすい。なお、硬磁性体層１０３ａは結晶方位の異なる集合からなる多結晶であり、各結晶が面内方向に磁気異方性を有する。この磁気異方性は結晶磁気異方性に由来するものである。 As described above, the alloy containing Cr and the like that constitutes the control layer 102 has a bcc structure. Therefore, the hard magnetic layer 103a forming the thin-film magnet 20 has a hcp (hexagonal close-packed) structure that facilitates crystal growth on the control layer 102 made of an alloy containing Cr or the like having a bcc structure. Is good. When the hard magnetic layer 103a having the hcp structure is crystal-grown on the bcc structure, the c axis of the hcp structure is easily oriented so as to be in-plane. Therefore, the thin film magnet 20 including the hard magnetic layer 103a tends to have magnetic anisotropy in the in-plane direction. The hard magnetic layer 103a is a polycrystal composed of aggregates having different crystal orientations, and each crystal has magnetic anisotropy in the in-plane direction. This magnetic anisotropy is derived from crystal magnetic anisotropy.
　なお、制御層１０２を構成するＣｒ等を含む合金及び硬磁性体層１０３ａを構成するＣｏ合金の結晶成長を促進するために、基板１０を１００℃～６００℃に加熱するとよい。この加熱により、制御層１０２を構成するＣｒ等を含む合金が結晶成長しやすくなり、ｈｃｐ構造を持つ硬磁性体層１０３ａが面内に磁化容易軸を持つように結晶配向されやすくなる。つまり、硬磁性体層１０３ａの面内に磁気異方性が付与されやすくなる。 The substrate 10 may be heated to 100 ° C. to 600 ° C. in order to promote crystal growth of the alloy containing Cr or the like forming the control layer 102 and the Co alloy forming the hard magnetic layer 103a. This heating facilitates crystal growth of the alloy containing Cr or the like forming the control layer 102 and facilitates crystal orientation of the hard magnetic layer 103a having the hcp structure so that the hard magnetic layer 103a has an in-plane easy magnetization axis. That is, magnetic anisotropy is easily imparted to the surface of the hard magnetic layer 103a.
　薄膜磁石２０を構成する非磁性体層１０３ｂは、Ｃｒ、Ｒｕ、Ｔｉ、Ｍｏ、Ｐｔ、Ｃｕ、Ｗ、Ｍｏ等の非磁性金属（以下では、非磁性体層１０３ｂを構成する非磁性金属と表記する。）により構成される。これらの中でも、非磁性体層１０３ｂを構成する非磁性金属は、ＣｒまたはＲｕであることが好ましい。なお、複数の非磁性体層１０３ｂのうち、それぞれの非磁性体層１０３ｂを構成する非磁性金属は、互いに等しくてもよく、互いに異なっていてもよい。
　また、非磁性体層１０３ｂの厚さは、硬磁性体層１０３ａの厚さよりも薄く、０．１ｎｍ以上５ｎｍ以下の範囲である。非磁性体層１０３ｂの厚さが５ｎｍよりも厚い場合、非磁性体層１０３ｂを介して対向する硬磁性体層１０３ａ同士の相互作用が弱くなり、薄膜磁石２０により感受素子３１に印加される磁界の強さが低下するおそれがある。 The non-magnetic layer 103b forming the thin-film magnet 20 is a non-magnetic metal such as Cr, Ru, Ti, Mo, Pt, Cu, W, Mo (hereinafter referred to as a non-magnetic metal forming the non-magnetic layer 103b). )). Among these, the nonmagnetic metal forming the nonmagnetic layer 103b is preferably Cr or Ru. Note that, among the plurality of nonmagnetic layers 103b, the nonmagnetic metals forming the respective nonmagnetic layers 103b may be the same or different from each other.
The thickness of the non-magnetic layer 103b is smaller than the thickness of the hard magnetic layer 103a and is in the range of 0.1 nm or more and 5 nm or less. When the thickness of the non-magnetic layer 103b is thicker than 5 nm, the interaction between the hard magnetic layers 103a facing each other via the non-magnetic layer 103b becomes weak, and the magnetic field applied to the sensing element 31 by the thin-film magnet 20. May decrease in strength.
　図１（ｂ）に戻り、絶縁層１０４は、非磁性の絶縁体で構成され、薄膜磁石２０と感受部３０との間を電気的に絶縁する。絶縁層１０４を構成する絶縁体としては、ＳｉＯ2、Ａｌ2Ｏ3、ＴｉＯ2等の酸化物、又は、Ｓｉ3Ｎ4、ＡｌＮ等の窒化物等が挙げられる。絶縁層１０４の厚さは、例えば０．０１μｍ～５０μｍである。 Returning to FIG. 1B, the insulating layer 104 is made of a non-magnetic insulator and electrically insulates the thin film magnet 20 and the sensing unit 30 from each other. Examples of the insulator forming the insulating layer 104 include oxides such as SiO 2 , Al 2 O 3 and TiO 2 , nitrides such as Si 3 N 4 and AlN. The insulating layer 104 has a thickness of, for example, 0.01 μm to 50 μm.
　感受部３０における感受素子３１は、長手方向に交差する方向、例えば直交する短手方向（幅方向）に一軸磁気異方性が付与されている。感受素子３１を構成する軟磁性体（軟磁性体層１０５）としては、Ｃｏを主成分とした合金に高融点金属Ｎｂ、Ｔａ、Ｗ等を添加したアモルファス合金（以下では、感受素子３１を構成するＣｏ合金と表記する。）を用いるのがよい。感受素子３１を構成するＣｏ合金としては、ＣｏＮｂＺｒ、ＣｏＦｅＴａ、ＣｏＷＺｒ等が挙げられる。感受素子３１を構成する軟磁性体（軟磁性体層１０５）の厚さは、例えば０．５μｍ～５μｍである。
　なお、長手方向に交差する方向とは、長手方向に対して４５°を超えた角度を有すればよい。 The sensitive element 31 in the sensitive section 30 is provided with uniaxial magnetic anisotropy in a direction intersecting the longitudinal direction, for example, in a transverse direction (width direction) orthogonal to each other. The soft magnetic material (soft magnetic material layer 105) forming the sensing element 31 is an amorphous alloy in which a refractory metal Nb, Ta, W, or the like is added to an alloy containing Co as a main component (hereinafter, the sensing element 31 is formed. It is preferable to use a Co alloy). Examples of the Co alloy forming the sensitive element 31 include CoNbZr, CoFeTa, CoWZr, and the like. The thickness of the soft magnetic material (soft magnetic material layer 105) forming the sensing element 31 is, for example, 0.5 μm to 5 μm.
The direction intersecting with the longitudinal direction may have an angle of more than 45 ° with respect to the longitudinal direction.
　密着層１０１、制御層１０２、硬磁性体層１０３ａおよび非磁性体層１０３ｂ（薄膜磁石２０）、絶縁層１０４は、平面形状が四角形（図１（ａ）参照）になるように加工されている。そして、露出した側面のうち、対向する二つの側面において、薄膜磁石２０がＮ極（図１（ｂ）における（Ｎ））及びＳ極（図１（ｂ）における（Ｓ））となっている。なお、薄膜磁石２０のＮ極とＳ極とを結ぶ線が、感受部３０における感受素子３１の長手方向に向くようになっている。ここで、長手方向に向くとは、Ｎ極とＳ極とを結ぶ線と長手方向とがなす角度が４５°未満であることをいう。なお、Ｎ極とＳ極とを結ぶ線と長手方向とがなす角度は、小さいほどよい。 The adhesion layer 101, the control layer 102, the hard magnetic layer 103a, the non-magnetic layer 103b (thin film magnet 20), and the insulating layer 104 are processed so that the planar shape is a quadrangle (see FIG. 1A). . The thin-film magnet 20 has an N pole ((N) in FIG. 1B) and an S pole ((S) in FIG. 1B) on two opposing side surfaces of the exposed side surfaces. . The line connecting the N pole and the S pole of the thin film magnet 20 is oriented in the longitudinal direction of the sensing element 31 in the sensing section 30. Here, “toward the longitudinal direction” means that the angle formed by the line connecting the N pole and the S pole and the longitudinal direction is less than 45 °. The angle formed by the line connecting the N pole and the S pole and the longitudinal direction is preferably as small as possible.
　磁気センサ１において、薄膜磁石２０のＮ極から出た磁力線は、一旦磁気センサ１の外部に出る。そして、一部の磁力線が、ヨーク４０ａを介して感受素子３１を透過し、ヨーク４０ｂを介して再び外部にでる。そして、感受素子３１を透過した磁力線が、感受素子３１を透過しない磁力線とともに薄膜磁石２０のＳ極に戻る。つまり、薄膜磁石２０は、感受素子３１の長手方向に磁界を印加する。
　なお、薄膜磁石２０のＮ極とＳ極とをまとめて両磁極と表記し、Ｎ極とＳ極とを区別しない場合は磁極と表記する。 In the magnetic sensor 1, the magnetic force line emitted from the N pole of the thin-film magnet 20 once goes out of the magnetic sensor 1. Then, some of the magnetic lines of force pass through the sensing element 31 via the yoke 40a, and go out again via the yoke 40b. Then, the magnetic force line that has passed through the sensing element 31 returns to the S pole of the thin film magnet 20 together with the magnetic force line that does not pass through the sensing element 31. That is, the thin film magnet 20 applies a magnetic field in the longitudinal direction of the sensitive element 31.
The N pole and the S pole of the thin-film magnet 20 are collectively referred to as both magnetic poles, and when the N pole and the S pole are not distinguished, they are referred to as magnetic poles.
　なお、図１（ａ）に示すように、ヨーク４０（ヨーク４０ａ、４０ｂ）は、基板１０の表面側から見た形状が、感受部３０に近づくにつれて狭くなっていくように構成されている。これは、感受部３０に磁界を集中させる（磁力線を集める）ためである。つまり、感受部３０における磁界を強くして感度のさらなる向上を図っている。なお、ヨーク４０（ヨーク４０ａ、４０ｂ）の感受部３０に対向する部分の幅を狭くしなくてもよい。 Note that, as shown in FIG. 1A, the yoke 40 ( yokes 40a and 40b) is configured such that the shape viewed from the surface side of the substrate 10 becomes narrower as it approaches the sensing unit 30. This is for concentrating a magnetic field on the sensing unit 30 (collecting magnetic force lines). That is, the magnetic field in the sensing unit 30 is strengthened to further improve the sensitivity. The width of the portion of the yoke 40 ( yokes 40a and 40b) facing the sensing unit 30 does not have to be narrowed.
　ここで、ヨーク４０（ヨーク４０ａ、４０ｂ）と感受部３０との間隔は、例えば１μｍ～１００μｍであればよい。 Here, the distance between the yoke 40 ( yokes 40a and 40b) and the sensing unit 30 may be, for example, 1 μm to 100 μm.
　ところで、薄膜磁石２０の磁気特性は、薄膜磁石２０を構成する硬磁性体の角型比（Ｍｒ／Ｍｓ）、保磁力（Ｈｃ）、硬磁性体の厚さ（Ｔ）等によって変化する。ここで、Ｍｒは、硬磁性体の残留磁化であり、Ｍｓは、硬磁性体の飽和磁化である。
　具体的には、薄膜磁石２０により感受素子３１に印加される磁界の強さは、薄膜磁石２０を構成する硬磁性体の残留磁化（Ｍｒ）と厚さ（Ｔ）との積（ＭｒＴ）に比例する。しかしながら、薄膜磁石２０を構成する硬磁性体の厚さ（Ｔ）を単純に厚くすると、硬磁性体の角型比（Ｍｒ／Ｍｓ）が低下する傾向がある（後述する図３（ａ）も参照）。ここで、硬磁性体の飽和磁化（Ｍｓ）は、硬磁性体の種類（材質）によって所定の値をとる。したがって、薄膜磁石２０を構成する硬磁性体の材質が同じ場合、薄膜磁石２０を構成する硬磁性体の厚さ（Ｔ）を単純に厚くすると、硬磁性体の残留磁化（Ｍｒ）が低下する。この結果、薄膜磁石２０を構成する硬磁性体の厚さ（Ｔ）を厚くした場合であっても、ＭｒＴは大きくならず、薄膜磁石２０により感受素子３１に印加される磁界の強さを大きくすることは困難である。 By the way, the magnetic characteristics of the thin-film magnet 20 change depending on the squareness ratio (Mr / Ms) of the hard magnetic material forming the thin-film magnet 20, the coercive force (Hc), the thickness (T) of the hard magnetic material, and the like. Here, Mr is the residual magnetization of the hard magnetic material, and Ms is the saturation magnetization of the hard magnetic material.
Specifically, the strength of the magnetic field applied to the sensing element 31 by the thin film magnet 20 is determined by the product (MrT) of the residual magnetization (Mr) and the thickness (T) of the hard magnetic material forming the thin film magnet 20. Proportional. However, if the thickness (T) of the hard magnetic material forming the thin-film magnet 20 is simply increased, the squareness ratio (Mr / Ms) of the hard magnetic material tends to decrease (see also FIG. 3A described later). reference). Here, the saturation magnetization (Ms) of the hard magnetic material takes a predetermined value depending on the type (material) of the hard magnetic material. Therefore, when the material of the hard magnetic material forming the thin film magnet 20 is the same, if the thickness (T) of the hard magnetic material forming the thin film magnet 20 is simply increased, the residual magnetization (Mr) of the hard magnetic material decreases. . As a result, even when the thickness (T) of the hard magnetic material forming the thin film magnet 20 is increased, MrT does not increase, and the strength of the magnetic field applied to the sensing element 31 by the thin film magnet 20 increases. Is difficult to do.
　また、薄膜磁石２０を構成する硬磁性体の厚さ（Ｔ）を単純に厚くすると、保磁力（Ｈｃ）が低下する傾向がある（後述する図３（ｂ）も参照）。そして、薄膜磁石２０を構成する硬磁性体の保磁力（Ｈｃ）が低い場合、磁気センサ１の周囲の磁界（外部磁界）の影響を受けて、薄膜磁石２０の残留磁化（Ｍｒ）が低下するおそれがある。 Also, if the thickness (T) of the hard magnetic material forming the thin-film magnet 20 is simply increased, the coercive force (Hc) tends to decrease (see also FIG. 3 (b) described later). When the coercive force (Hc) of the hard magnetic material forming the thin-film magnet 20 is low, the residual magnetization (Mr) of the thin-film magnet 20 is affected by the magnetic field (external magnetic field) around the magnetic sensor 1. There is a risk.
　図３（ａ）～（ｂ）は、薄膜磁石２０を構成する硬磁性体（硬磁性体層１０３ａ）の厚さと、薄膜磁石２０の磁気特性との関係を説明する図である。図３（ａ）は、薄膜磁石２０を構成する硬磁性体層１０３ａの厚さと、薄膜磁石２０の保磁力（Ｈｃ）との関係を示している。図３（ｂ）は、薄膜磁石２０を構成する硬磁性体層１０３ａの厚さと、薄膜磁石２０の角型比（Ｍｒ／Ｍｓ）との関係を示している。 FIGS. 3A and 3B are diagrams for explaining the relationship between the thickness of the hard magnetic material (hard magnetic material layer 103 a) forming the thin film magnet 20 and the magnetic characteristics of the thin film magnet 20. FIG. 3A shows the relationship between the thickness of the hard magnetic layer 103 a forming the thin film magnet 20 and the coercive force (Hc) of the thin film magnet 20. FIG. 3B shows the relationship between the thickness of the hard magnetic layer 103 a forming the thin film magnet 20 and the squareness ratio (Mr / Ms) of the thin film magnet 20.
　また、図３（ａ）～（ｂ）において、「単層」とは、薄膜磁石２０が一層の硬磁性体によって構成される場合を示しており、「厚さ」は、この一層の硬磁性体の厚さを意味する。一方、図３（ａ）～（ｂ）において、「多層」とは、本実施の形態のように、薄膜磁石２０が二層以上の硬磁性体層１０３ａと、非磁性体層１０３ｂとが交互に積層されて構成される場合を示しており、「厚さ」は、薄膜磁石２０を構成する複数の硬磁性体層１０３ａの厚さの総和を意味する。
　この例において、「単層」の薄膜磁石２０は、ＣｏＣｒＴａ（原子数比Ｃｏ：Ｃｒ：Ｔａ＝９０：８：２）からなる一層の硬磁性体により構成されている。また、「多層」の薄膜磁石２０は、厚さ５０ｎｍのＣｏＣｒＴａ（原子数比Ｃｏ：Ｃｒ：Ｔａ＝９０：８：２）からなる硬磁性体層１０３ａと、厚さ１ｎｍのＣｒからなる非磁性体層１０３ｂとを交互に積層し、且つ最上層の非磁性体層１０３ｂのみが厚さ１ｎｍのＲｕからなる構造を有している。なお、図３（ａ）～（ｂ）において「多層」のグラフに付している数字は、薄膜磁石２０を構成する硬磁性体層１０３ａの層数である。 Further, in FIGS. 3A and 3B, “single layer” indicates a case where the thin-film magnet 20 is composed of one hard magnetic material, and “thickness” indicates this one hard magnetic material. It means the thickness of the body. On the other hand, in FIGS. 3A and 3B, “multilayer” means that the thin-film magnet 20 is composed of two or more hard magnetic layers 103 a and non-magnetic layers 103 b alternately as in the present embodiment. The “thickness” means the total thickness of the plurality of hard magnetic layers 103a forming the thin film magnet 20.
In this example, the “single-layer” thin-film magnet 20 is composed of a single hard magnetic body made of CoCrTa (atomic ratio Co: Cr: Ta = 90: 8: 2). The "multilayer" thin-film magnet 20 includes a hard magnetic layer 103a made of CoCrTa (atomic ratio Co: Cr: Ta = 90: 8: 2) having a thickness of 50 nm and a non-magnetic layer made of Cr having a thickness of 1 nm. The body layers 103b are alternately laminated, and only the uppermost nonmagnetic layer 103b has a structure of Ru having a thickness of 1 nm. The numbers attached to the “multilayer” graphs in FIGS. 3A and 3B indicate the number of hard magnetic layers 103 a constituting the thin film magnet 20.
　図３（ａ）に示すように、薄膜磁石２０が一層の硬磁性体により構成される場合（単層）、硬磁性体の厚さが厚くなるに従い、保磁力（Ｈｃ）が低下している。
　これに対し、薄膜磁石２０が二層以上の硬磁性体層１０３ａを有する場合（多層）、硬磁性体層１０３ａの層数が増加し硬磁性体の厚さ（硬磁性体層１０３ａの厚さの総和）が厚くなった場合であっても、保磁力（Ｈｃ）の低下が抑制されている。 As shown in FIG. 3A, when the thin film magnet 20 is composed of one layer of hard magnetic material (single layer), the coercive force (Hc) decreases as the thickness of the hard magnetic material increases. .
On the other hand, when the thin-film magnet 20 has two or more hard magnetic layers 103a (multilayer), the number of hard magnetic layers 103a increases and the thickness of the hard magnetic layer (the thickness of the hard magnetic layer 103a) increases. The total coercive force (Hc) is suppressed even when the total coercive force (Hc) is increased.
　同様に、図３（ｂ）に示すように、薄膜磁石２０が一層の硬磁性体により構成される場合（単層）、硬磁性体の厚さが厚くなるに従い、角型比（Ｍｒ／Ｍｓ）が低下している。
　これに対し、薄膜磁石２０が二層以上の硬磁性体層１０３ａを有する場合（多層）、硬磁性体層１０３ａの層数が増加し硬磁性体の厚さ（硬磁性体層１０３ａの厚さの総和、Ｔ）が厚くなった場合であっても、角型比（Ｍｒ／Ｍｓ）の低下が抑制されている。 Similarly, as shown in FIG. 3B, when the thin-film magnet 20 is composed of one layer of hard magnetic material (single layer), the squareness ratio (Mr / Ms) increases as the thickness of the hard magnetic material increases. ) Is falling.
On the other hand, when the thin-film magnet 20 has two or more hard magnetic layers 103a (multilayer), the number of hard magnetic layers 103a increases and the thickness of the hard magnetic layer (the thickness of the hard magnetic layer 103a) increases. Even if the total sum of the above, T) becomes thicker, the decrease of the squareness ratio (Mr / Ms) is suppressed.
　このように、本実施の形態の磁気センサ１では、薄膜磁石２０が二層以上の硬磁性体層１０３ａと非磁性体層１０３ｂとが交互に積層された構造を有することで、保磁力（Ｈｃ）および角型比（Ｍｒ／Ｍｓ）の低下を抑制しながら、硬磁性体の厚さ（硬磁性体層１０３ａの厚さの総和、Ｔ）を大きくすることができる。
　この結果、本実施の形態の磁気センサ１では、薄膜磁石２０を構成する硬磁性体の残留磁化（Ｍｒ）と厚さ（Ｔ）との積（ＭｒＴ）を大きくすることができ、薄膜磁石２０により感受素子３１に印加される磁界の強さを大きくすることが可能となる。また、本実施の形態の磁気センサ１では、薄膜磁石２０の保磁力（Ｈｃ）の低下を抑制することで、外部磁界の影響によって薄膜磁石２０の残留磁化（Ｍｒ）が低下することを抑制できる。 As described above, in the magnetic sensor 1 according to the present embodiment, the thin-film magnet 20 has a structure in which the hard magnetic layer 103a and the non-magnetic layer 103b, which are two or more layers, are alternately stacked, and thus the coercive force (Hc ) And the squareness ratio (Mr / Ms) are suppressed from decreasing, the thickness of the hard magnetic material (the total thickness of the hard magnetic material layer 103a, T) can be increased.
As a result, in the magnetic sensor 1 according to the present embodiment, the product (MrT) of the residual magnetization (Mr) and the thickness (T) of the hard magnetic material forming the thin film magnet 20 can be increased, and the thin film magnet 20 can be made. This makes it possible to increase the strength of the magnetic field applied to the sensing element 31. Further, in the magnetic sensor 1 of the present embodiment, by suppressing the decrease of the coercive force (Hc) of the thin film magnet 20, it is possible to suppress the decrease of the residual magnetization (Mr) of the thin film magnet 20 due to the influence of the external magnetic field. .
［磁気センサ１の製造方法］
　次に磁気センサ１の製造方法の一例を説明する。
　図４（ａ）～（ｄ）および図５（ａ）～（ｄ）は、磁気センサ１の製造方法の一例を説明する図である。図４（ａ）～（ｄ）および図５（ａ）～（ｄ）は、磁気センサ１の製造方法における工程を示す。なお、図４（ａ）～（ｄ）および図５（ａ）～（ｄ）は、代表的な工程であって、他の工程を含んでいてもよい。そして、工程は、図４（ａ）～（ｄ）、図５（ａ）～（ｄ）の順に進む。図４（ａ）～（ｄ）および図５（ａ）～（ｄ）は、図１（ａ）のＩＢ－ＩＢ線での断面図に対応する。 [Manufacturing Method of Magnetic Sensor 1]
Next, an example of a method of manufacturing the magnetic sensor 1 will be described.
FIGS. 4A to 4D and FIGS. 5A to 5D are diagrams illustrating an example of a method of manufacturing the magnetic sensor 1. 4A to 4D and FIGS. 5A to 5D show steps in the method of manufacturing the magnetic sensor 1. Note that FIGS. 4A to 4D and FIGS. 5A to 5D are representative steps, and may include other steps. Then, the process proceeds in the order of FIGS. 4A to 4D and FIGS. 5A to 5D. FIGS. 4A to 4D and FIGS. 5A to 5D correspond to the cross-sectional views taken along the line IB-IB in FIG. 1A.
　基板１０は、前述したように、非磁性材料からなる基板であって、例えばガラス、サファイアといった酸化物基板やシリコン等の半導体基板、あるいは、アルミニウム、ステンレススティール、ニッケルリンメッキを施した金属等の金属基板である。基板１０には、研磨機などを用いて、例えば曲率半径Ｒａが０．１ｎｍ～１００ｎｍの筋状の溝又は筋状の凹凸が設けられていてもよい。なお、この筋状の溝又は筋状の凹凸の筋の方向は、硬磁性体層１０３ａおよび非磁性体層１０３ｂによって構成される薄膜磁石２０のＮ極とＳ極とを結ぶ方向に設けられているとよい。このようにすることで、硬磁性体層１０３ａにおける結晶成長が、溝の方向へ促進される。よって、硬磁性体層１０３ａおよび非磁性体層１０３ｂにより構成される薄膜磁石２０の磁化容易軸がより溝方向（薄膜磁石２０のＮ極とＳ極とを結ぶ方向）に向きやすい。つまり、薄膜磁石２０の着磁をより容易にする。 As described above, the substrate 10 is a substrate made of a non-magnetic material, for example, an oxide substrate such as glass or sapphire, a semiconductor substrate such as silicon, or a metal such as aluminum, stainless steel, or nickel-phosphorus plated metal. It is a metal substrate. The substrate 10 may be provided with streak-shaped grooves or streak-shaped irregularities having a radius of curvature Ra of 0.1 nm to 100 nm, for example, by using a polishing machine or the like. The direction of the streak-shaped groove or streak-shaped uneven line is provided in the direction connecting the N pole and the S pole of the thin-film magnet 20 constituted by the hard magnetic layer 103a and the nonmagnetic layer 103b. I hope you are there. By doing so, crystal growth in the hard magnetic layer 103a is promoted in the groove direction. Therefore, the easy axis of magnetization of the thin-film magnet 20 constituted by the hard magnetic layer 103a and the non-magnetic layer 103b is more likely to be oriented in the groove direction (the direction connecting the N pole and the S pole of the thin-film magnet 20). That is, the magnetization of the thin film magnet 20 is made easier.
　ここでは、基板１０は、一例として直径約９５ｍｍ、厚さ約０．５ｍｍのガラスとして説明する。磁気センサ１の平面形状が数ｍｍ角である場合、基板１０上には、複数の磁気センサ１が一括して製造され、後に個々の磁気センサ１に分割（切断）される。図４（ａ）～（ｄ）および図５（ａ）～（ｄ）では、中央に表記する一個の磁気センサ１に着目するが、左右に隣接する磁気センサ１の一部を合わせて示す。なお、隣接する磁気センサ１間の境界を一点鎖線で示す。 Here, the substrate 10 will be described as an example of glass having a diameter of about 95 mm and a thickness of about 0.5 mm. When the planar shape of the magnetic sensor 1 is a few mm square, a plurality of magnetic sensors 1 are collectively manufactured on the substrate 10 and then divided (cut) into individual magnetic sensors 1. In FIGS. 4A to 4D and FIGS. 5A to 5D, one magnetic sensor 1 shown in the center is focused, but a part of the magnetic sensors 1 adjacent to the left and right is also shown together. The boundary between the adjacent magnetic sensors 1 is indicated by a chain line.
　図４（ａ）に示すように、基板１０を洗浄した後、基板１０の一方の面（以下、表面と表記する。）上に、密着層１０１、制御層１０２を順に成膜（体積）する。
　まず、Ｃｒ又はＮｉを含む合金である密着層１０１、Ｃｒ等を含む合金である制御層１０２を順に連続して成膜（堆積）する。この成膜は、スパッタリング法などにより行うことができる。それぞれの材料で形成された複数のターゲットに順に対面するように、基板１０を移動させることで密着層１０１及び制御層１０２が基板１０上に順に積層される。前述したように、制御層１０２の形成では、結晶成長を促進するために、基板１０を例えば１００℃～６００℃に加熱するとよい。 As shown in FIG. 4A, after cleaning the substrate 10, the adhesion layer 101 and the control layer 102 are sequentially formed (volume) on one surface (hereinafter referred to as the surface) of the substrate 10. .
First, the adhesion layer 101, which is an alloy containing Cr or Ni, and the control layer 102, which is an alloy containing Cr or the like, are successively formed (deposited). This film formation can be performed by a sputtering method or the like. The adhesion layer 101 and the control layer 102 are sequentially stacked on the substrate 10 by moving the substrate 10 so as to sequentially face the plurality of targets formed of the respective materials. As described above, in forming the control layer 102, the substrate 10 may be heated to, for example, 100 ° C. to 600 ° C. in order to promote crystal growth.
　なお、密着層１０１の成膜では、基板１０の加熱を行ってもよく、行わなくてもよい。基板１０の表面に吸着している水分などを除去するために、密着層１０１を成膜する前に、基板１０を加熱してもよい。 The deposition of the adhesion layer 101 may or may not be performed on the substrate 10. The substrate 10 may be heated before the adhesion layer 101 is formed in order to remove moisture or the like adsorbed on the surface of the substrate 10.
　次に、図４（ｂ）～（ｃ）に示すように、制御層１０２の成膜に続けて、硬磁性体層１０３ａを構成するＣｏ合金と、非磁性体層１０３ｂを構成する非磁性金属とを、予め定められた回数だけ、交互に成膜する。この成膜は、スパッタリング法などにより行える。硬磁性体層１０３ａの材料で形成されたターゲットと非磁性体層１０３ｂの材料で形成されたターゲットとに交互に対面するように、基板１０を移動させることで、制御層１０２上に、硬磁性体層１０３ａと非磁性体層１０３ｂとが交互に積層される。前述したように、硬磁性体層１０３ａおよび非磁性体層１０３ｂの成膜は、硬磁性体層１０３ａの結晶成長を促進するために、基板１０を例えば１００℃～６００℃に加熱するとよい。 Next, as shown in FIGS. 4B to 4C, following the film formation of the control layer 102, the Co alloy forming the hard magnetic layer 103a and the nonmagnetic metal forming the nonmagnetic layer 103b are formed. And are alternately formed a predetermined number of times. This film formation can be performed by a sputtering method or the like. By moving the substrate 10 so as to alternately face the target formed of the material of the hard magnetic layer 103a and the target formed of the material of the nonmagnetic layer 103b, the hard magnetic layer is formed on the control layer 102. The body layers 103a and the nonmagnetic layers 103b are alternately laminated. As described above, in forming the hard magnetic layer 103a and the non-magnetic layer 103b, the substrate 10 may be heated to, for example, 100 ° C. to 600 ° C. in order to promote crystal growth of the hard magnetic layer 103a.
　この例では、硬磁性体層１０３ａと非磁性体層１０３ｂとを、交互に４層ずつ成膜している。付言すると、この例では、非磁性体層１０３ｂが最上層となるように、硬磁性体層１０３ａおよび非磁性体層１０３ｂを成膜している。これにより、例えば硬磁性体層１０３ａおよび非磁性体層１０３ｂの成膜後、絶縁層１０４を成膜する前に、基板１０をスパッタリング装置等の外へ露出させた場合に、硬磁性体層１０３ａが酸化することが抑制される。
　硬磁性体層１０３ａの酸化のおそれがない場合等では、非磁性体層１０３ｂを設けずに硬磁性体層１０３ａが最上層になるようにしてもよい。 In this example, four hard magnetic layers 103a and four non-magnetic layers 103b are alternately formed. In addition, in this example, the hard magnetic layer 103a and the nonmagnetic layer 103b are formed such that the nonmagnetic layer 103b is the uppermost layer. Accordingly, for example, when the substrate 10 is exposed to the outside of a sputtering device or the like after forming the hard magnetic layer 103a and the non-magnetic layer 103b and before forming the insulating layer 104, the hard magnetic layer 103a is formed. Is suppressed from being oxidized.
When there is no risk of oxidation of the hard magnetic layer 103a, the hard magnetic layer 103a may be the uppermost layer without providing the non-magnetic layer 103b.
　次に、図４（ｄ）に示すように、ＳｉＯ2、Ａｌ2Ｏ3、ＴｉＯ2等の酸化物、又は、Ｓｉ3Ｎ4、ＡｌＮ等の窒化物等である絶縁層１０４を成膜（堆積）する。絶縁層１０４の成膜は、プラズマＣＶＤ法、反応性スパッタリング法などにより行える。 Next, as shown in FIG. 4D, an insulating layer 104 made of an oxide such as SiO 2 , Al 2 O 3 or TiO 2 or a nitride such as Si 3 N 4 or AlN is formed ( accumulate. The insulating layer 104 can be formed by a plasma CVD method, a reactive sputtering method, or the like.
　そして、図５（ａ）に示すように、感受部３０が形成される部分及びヨーク４０（ヨーク４０ａ、４０ｂ）が形成される部分を開口とするフォトレジストによるパターン（レジストパターン）１１１を、公知のフォトリソグラフィ技術により形成する。 Then, as shown in FIG. 5A, a photoresist pattern (resist pattern) 111 having openings at portions where the sensitive portions 30 are formed and portions where the yoke 40 ( yokes 40a and 40b) is formed is known. It is formed by the photolithography technology.
　そして、図５（ｂ）に示すように、感受素子３１を構成するＣｏ合金である軟磁性体層１０５を成膜（堆積）する。軟磁性体層１０５の成膜は、例えばスパッタリング法を用いて行える。 Then, as shown in FIG. 5B, the soft magnetic layer 105, which is a Co alloy forming the sensing element 31, is formed (deposited). The soft magnetic layer 105 can be formed by, for example, a sputtering method.
　図５（ｃ）に示すように、レジストパターン１１１を除去するとともに、レジストパターン１１１上の軟磁性体層１０５を除去（リフトオフ）する。これにより、軟磁性体層１０５による感受部３０及びヨーク４０（ヨーク４０ａ、４０ｂ）が形成される。つまり、感受部３０とヨーク４０とが、１回の軟磁性体層１０５の成膜で形成される。この感受部３０を形成する工程を、感受部形成工程と呼ぶ。なお、感受部形成工程には、軟磁性体層１０５を形成する工程又は／及びヨーク４０を形成する工程が含まれていてもよい。 As shown in FIG. 5C, the resist pattern 111 is removed and the soft magnetic layer 105 on the resist pattern 111 is removed (lifted off). As a result, the sensitive portion 30 and the yoke 40 (the yokes 40a and 40b) are formed by the soft magnetic layer 105. That is, the sensing section 30 and the yoke 40 are formed by film-forming the soft magnetic layer 105 once. The process of forming the sensitive portion 30 is called a sensitive portion forming process. Note that the susceptor forming step may include a step of forming the soft magnetic layer 105 and / or a step of forming the yoke 40.
　この後、軟磁性体層１０５には、感受部３０における感受素子３１の幅方向に一軸磁気異方性を付与する。この軟磁性体層１０５への一軸磁気異方性の付与は、例えば３ｋＧ（０．３Ｔ）の回転磁場中における４００℃での熱処理（回転磁場中熱処理）と、それに引き続く３ｋＧ（０．３Ｔ）の静磁場中における４００℃での熱処理（静磁場中熱処理）とで行える。この時、ヨーク４０を構成する軟磁性体層１０５にも同様の一軸磁気異方性が付与される。しかし、ヨーク４０は、磁気回路としての役割を果たせばよく、一軸磁気異方性が付与されてもよい。 After that, uniaxial magnetic anisotropy is given to the soft magnetic layer 105 in the width direction of the sensing element 31 in the sensing section 30. The uniaxial magnetic anisotropy is imparted to the soft magnetic layer 105 by heat treatment at 400 ° C. in a rotating magnetic field of 3 kG (0.3 T) (heat treatment in a rotating magnetic field) and subsequent 3 kG (0.3 T). Heat treatment at 400 ° C. in a static magnetic field (heat treatment in a static magnetic field). At this time, the same uniaxial magnetic anisotropy is also given to the soft magnetic layer 105 that constitutes the yoke 40. However, the yoke 40 only needs to play a role as a magnetic circuit, and may have uniaxial magnetic anisotropy.
　次に、薄膜磁石２０を構成する硬磁性体層１０３ａを着磁する。硬磁性体層１０３ａに対する着磁は、静磁場中又はパルス状の磁場中において、硬磁性体層１０３ａの保磁力より大きい磁界を、硬磁性体層１０３ａの磁化が飽和するまで印加することで行える。なお、上述した薄膜磁石２０を構成する硬磁性体層１０３ａおよび非磁性体層１０３ｂを成膜する工程、および硬磁性体層１０３ａを着磁する工程は、磁気異方性が面内方向に制御された薄膜磁石２０を形成するための工程であるから、これらを併せて、薄膜磁石形成工程と呼ぶことがある。 Next, the hard magnetic layer 103a constituting the thin film magnet 20 is magnetized. The magnetization of the hard magnetic layer 103a can be performed by applying a magnetic field larger than the coercive force of the hard magnetic layer 103a in a static magnetic field or a pulsed magnetic field until the magnetization of the hard magnetic layer 103a is saturated. . The magnetic anisotropy is controlled in the in-plane direction in the steps of forming the hard magnetic layer 103a and the non-magnetic layer 103b that form the thin-film magnet 20 and the step of magnetizing the hard magnetic layer 103a. Since these are the steps for forming the thin film magnet 20 thus formed, they may be collectively referred to as a thin film magnet forming step.
　この後、図５（ｄ）に示すように、基板１０上に形成された複数の磁気センサ１を個々の磁気センサ１に分割（切断）する。つまり、図１（ａ）の平面図に示したように、平面形状が四角形になるように、基板１０、密着層１０１、制御層１０２、硬磁性体層１０３ａ、非磁性体層１０３ｂ、絶縁層１０４及び軟磁性体層１０５を切断する。すると、分割（切断）された硬磁性体層１０３ａおよび非磁性体層１０３ｂの側面に薄膜磁石２０の磁極（Ｎ極及びＳ極）が露出する。こうして、着磁された硬磁性体層１０３ａは、薄膜磁石２０になる。この分割（切断）は、ダイシング法やレーザカッティング法などにより行える。 After that, as shown in FIG. 5D, the plurality of magnetic sensors 1 formed on the substrate 10 are divided (cut) into individual magnetic sensors 1. That is, as shown in the plan view of FIG. 1A, the substrate 10, the adhesion layer 101, the control layer 102, the hard magnetic layer 103a, the nonmagnetic layer 103b, and the insulating layer are formed so that the planar shape is a quadrangle. The 104 and the soft magnetic layer 105 are cut. Then, the magnetic poles (N pole and S pole) of the thin film magnet 20 are exposed on the side surfaces of the divided (cut) hard magnetic layer 103a and non-magnetic layer 103b. The hard magnetic layer 103a thus magnetized becomes the thin film magnet 20. This division (cutting) can be performed by a dicing method, a laser cutting method, or the like.
　なお、図５（ｄ）の複数の磁気センサ１を個々の磁気センサ１に分割する工程の前に、基板１０上において隣接する磁気センサ１の間の密着層１０１、制御層１０２、硬磁性体層１０３ａ、非磁性体層１０３ｂ及び絶縁層１０４を、平面形状が四角形（図１（ａ）に示した磁気センサ１の平面形状）になるようにエッチング除去してもよい。そして、露出した基板１０を分割（切断）してもよい。
　また、図４（ａ）～（ｄ）の積層体を形成する工程の後に、密着層１０１、制御層１０２、硬磁性体層１０３ａ、非磁性体層１０３ｂ及び絶縁層１０４を、平面形状が四角形（図１（ａ）に示した磁気センサ１の平面形状）になるように加工してもよい。
　なお、図４（ａ）～（ｄ）および図５（ａ）～（ｄ）に示した製造方法は、これらの製造方法に比べ、工程が簡略化される。 In addition, before the step of dividing the plurality of magnetic sensors 1 of FIG. 5D into individual magnetic sensors 1, the adhesion layer 101, the control layer 102, the hard magnetic material between the adjacent magnetic sensors 1 on the substrate 10 are formed. The layer 103a, the nonmagnetic layer 103b, and the insulating layer 104 may be removed by etching so that the planar shape becomes a quadrangle (the planar shape of the magnetic sensor 1 shown in FIG. 1A). Then, the exposed substrate 10 may be divided (cut).
After the step of forming the stacked body of FIGS. 4A to 4D, the planar shape of the adhesion layer 101, the control layer 102, the hard magnetic layer 103a, the nonmagnetic layer 103b, and the insulating layer 104 is quadrangular. You may process so that it may become (planar shape of the magnetic sensor 1 shown to Fig.1 (a)).
The manufacturing method shown in FIGS. 4A to 4D and FIGS. 5A to 5D has a simplified process as compared with these manufacturing methods.
　このようにして、磁気センサ１が製造される。なお、軟磁性体層１０５への一軸異方性の付与及び／又は薄膜磁石２０の着磁は、図５（ｄ）の磁気センサ１を個々の磁気センサ１に分割する工程の後に、磁気センサ１毎又は複数の磁気センサ１に対して行ってもよい。 In this way, the magnetic sensor 1 is manufactured. Note that the uniaxial anisotropy is imparted to the soft magnetic layer 105 and / or the thin film magnet 20 is magnetized after the step of dividing the magnetic sensor 1 of FIG. You may perform it for every 1 or several magnetic sensor 1.
　なお、制御層１０２を備えない場合には、複数の硬磁性体層１０３ａを成膜後、８００℃以上に加熱して結晶成長させることで、面内に磁気異方性を付与することが必要となる。しかし、第１の実施の形態が適用される磁気センサ１のように、制御層１０２を備える場合には、制御層１０２により結晶成長が促進されるため、８００℃以上のような高温による結晶成長を要しない。 If the control layer 102 is not provided, it is necessary to impart in-plane magnetic anisotropy by depositing a plurality of hard magnetic layers 103a and then heating to 800 ° C. or higher to grow crystals. Becomes However, when the control layer 102 is provided as in the magnetic sensor 1 to which the first embodiment is applied, crystal growth is promoted by the control layer 102, so crystal growth at a high temperature of 800 ° C. or higher is performed. Does not need
　また、感受部３０の感受素子３１への一軸異方性の付与は、上記の回転磁場中熱処理及び静磁場中熱処理で行う代わりに、感受素子３１を構成するＣｏ合金である軟磁性体層１０５の堆積時にマグネトロンスパッタリング法を用いて行ってもよい。マグネトロンスパッタリング法では、磁石（マグネット）を用いて磁界を形成し、放電によって発生した電子をターゲットの表面に閉じ込める（集中させる）。これにより、電子とガスとの衝突確率を増加させてガスの電離を促進し、膜の堆積速度（成膜速度）を向上させる。このマグネトロンスパッタリング法に用いられる磁石（マグネット）が形成する磁界により、軟磁性体層１０５の堆積と同時に、軟磁性体層１０５に一軸異方性が付与される。このようにすることで、回転磁場中熱処理及び静磁場中熱処理で行う一軸異方性を付与する工程が省略できる。 Further, the uniaxial anisotropy is imparted to the sensing element 31 of the sensing section 30, instead of performing the heat treatment in the rotating magnetic field and the heat treatment in the static magnetic field as described above, the soft magnetic layer 105 which is a Co alloy constituting the sensing element 31. It may be performed by using a magnetron sputtering method at the time of depositing. In the magnetron sputtering method, a magnetic field is formed using a magnet, and the electrons generated by the discharge are confined (concentrated) on the surface of the target. This increases the probability of collision between electrons and gas, promotes ionization of gas, and improves the deposition rate (deposition rate) of the film. A uniaxial anisotropy is imparted to the soft magnetic material layer 105 at the same time as the soft magnetic material layer 105 is deposited by a magnetic field formed by a magnet used in the magnetron sputtering method. This makes it possible to omit the step of imparting uniaxial anisotropy in the heat treatment in the rotating magnetic field and the heat treatment in the static magnetic field.
　以上、本発明の実施の形態を説明したが、本発明の趣旨に反しない限りにおいて様々な変形を行っても構わない。 Although the embodiments of the present invention have been described above, various modifications may be made without departing from the spirit of the present invention.
１…磁気センサ、１０…基板、２０…薄膜磁石、３０…感受部、３１…感受素子、３２…接続部、３３…端子部、４０、４０ａ、４０ｂ…ヨーク、１０１…密着層、１０２…制御層、１０３ａ…硬磁性体層、１０３ｂ…非磁性体層、１０４…絶縁層、１０５…軟磁性体層 DESCRIPTION OF SYMBOLS 1 ... Magnetic sensor, 10 ... Substrate, 20 ... Thin film magnet, 30 ... Sensing part, 31 ... Sensing element, 32 ... Connection part, 33 ... Terminal part, 40, 40a, 40b ... Yoke, 101 ... Adhesion layer, 102 ... Control Layer, 103a ... Hard magnetic layer, 103b ... Nonmagnetic layer, 104 ... Insulating layer, 105 ... Soft magnetic layer

Claims (7)

  1. 　Ｃｏを含む硬磁性体で構成される２層以上の硬磁性体層と、非磁性体で構成され厚さが当該硬磁性体層の厚さ以下である非磁性体層とが交互に積層され、面内方向に磁気異方性を有する薄膜磁石と、
    　軟磁性体で構成されるとともに、前記薄膜磁石に対向して配置され、長手方向と短手方向とを有し、当該長手方向が当該薄膜磁石の発生する磁界の方向を向くとともに、当該長手方向と交差する方向に一軸磁気異方性を有し、磁気インピーダンス効果により磁界を感受する感受素子と
    を備える磁気センサ。     Two or more hard magnetic layers composed of a hard magnetic material containing Co and non-magnetic layers composed of a non-magnetic material and having a thickness equal to or less than the thickness of the hard magnetic layer are alternately laminated. , A thin film magnet having magnetic anisotropy in the in-plane direction,
    It is composed of a soft magnetic material and is arranged so as to face the thin film magnet, has a longitudinal direction and a lateral direction, and the longitudinal direction faces the direction of the magnetic field generated by the thin film magnet, and the longitudinal direction. A magnetic sensor having a sensitizing element which has uniaxial magnetic anisotropy in a direction intersecting with and which senses a magnetic field by a magnetic impedance effect.
  2. 　前記薄膜磁石の前記硬磁性体層は、Ｃｏに加えて、Ｃｒ、Ｔａ、Ｐｔ、Ｒｕ、Ｎｉ、Ｗ、Ｂ、Ｖ、Ｃｕから選択される少なくとも１つの金属を含む硬磁性体で構成されることを特徴とする請求項１に記載の磁気センサ。 The hard magnetic layer of the thin-film magnet is made of a hard magnetic material containing, in addition to Co, at least one metal selected from Cr, Ta, Pt, Ru, Ni, W, B, V, and Cu. The magnetic sensor according to claim 1, wherein:
  3. 　前記薄膜磁石の前記硬磁性体層は、ＣｏＣｒＴａまたはＣｏＣｒＮｉからなる硬磁性体で構成されることを特徴とする請求項２に記載の磁気センサ。 The magnetic sensor according to claim 2, wherein the hard magnetic layer of the thin-film magnet is made of a hard magnetic body made of CoCrTa or CoCrNi.
  4. 　前記薄膜磁石は、それぞれの前記硬磁性体層の厚さが１５０ｎｍ以下であることを特徴とする請求項１に記載の磁気センサ。 The magnetic sensor according to claim 1, wherein each of the thin film magnets has a thickness of the hard magnetic layer of 150 nm or less.
  5. 　前記薄膜磁石は、前記感受素子に対向する面が前記非磁性体層により構成されていることを特徴とする請求項１に記載の磁気センサ。 The magnetic sensor according to claim 1, wherein the thin-film magnet has a surface facing the sensing element formed of the non-magnetic layer.
  6. 　非磁性の基板上に、Ｃｏを含む硬磁性体からなる２層以上の硬磁性体層と、非磁性体からなる非磁性体層とを交互に積層して、磁気異方性が面内方向に制御された薄膜磁石を形成する薄膜磁石形成工程と、
    　前記薄膜磁石の発生する磁束が透過する方向と交差する方向に一軸磁気異方性を有する感受素子を備える感受部を形成する感受部形成工程と、
    を含む、磁気センサの製造方法。     Two or more hard magnetic layers made of a hard magnetic material containing Co and nonmagnetic layers made of a nonmagnetic material are alternately laminated on a nonmagnetic substrate so that the magnetic anisotropy is in the in-plane direction. A thin film magnet forming step of forming a thin film magnet controlled to
    A susceptor forming step of forming a susceptor including a susceptor having uniaxial magnetic anisotropy in a direction intersecting a direction in which a magnetic flux generated by the thin film magnet is transmitted;
    A method of manufacturing a magnetic sensor, comprising:
  7. 　前記薄膜磁石形成工程は、前記非磁性体層が最上層となるように、前記硬磁性体層と当該非磁性体層とを交互に積層することを特徴とする請求項６に記載の磁気センサの製造方法。 The magnetic sensor according to claim 6, wherein in the thin-film magnet forming step, the hard magnetic layer and the non-magnetic layer are alternately laminated so that the non-magnetic layer is the uppermost layer. Manufacturing method.
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