JPH10326919A - Magneto resistive device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily optimize magnetic characteristics for product specifications by utilizing a magnetic elastic effect, by arranging and forming a magnetic film with the magnetic resistance effect for detecting a magnetic field on a flexible substrate. SOLUTION: In an element 1, a magnetic film 15 with a magnetic resistance effect for detecting a magnetic field, and conductor electrode films 21 and 25 that are connected to the magnetic film 15 and feed current to it, are arranged and formed on the surface of a flexible substrate 10. Then, the magnetic film 15 is formed in a specific pattern shape to detect the magnetic field and both edge parts 15a and 15a are connected to one portion of the conductor electrode films 21 and 25. Then, for example, the flexible substrate 10 is curved by a flat-plate-shaped auxiliary member 9 with curved parts 9a and 9a, and is kept flat at a location where the magnetic film 15 is formed and a curved part 11 is formed, thus preventing a projecting part that interferes with the detection of the magnetic field from being generated on a surface where the magnetic film 15 is formed, and hence extremely reducing a distance to an object to be detected.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetoresistance effect element, and more particularly to a magnetic field detection element such as a magnetic field sensor used for rotation detection and position detection.

[0002]

2. Description of the Related Art A magnetoresistive element is an element for measuring the intensity of a magnetic field using a phenomenon in which the electric resistance of a ferromagnetic metal changes due to a change in an external magnetic field (magnetoresistive effect, MR effect). As the single-layer magnetic film, a long-known magnetic anisotropic magnetoresistance effect was used, but recently,
For example, JP-A-5-259530 and JP-A-7-7
As disclosed in Japanese Patent No. 7531, an element using a giant magnetoresistance effect (GMR effect) using a magnetic film having a multilayer structure has been developed.

[0003] Also, National Technical Report, 4
Vol. 2, No. 4, pp. 465-472, (NiFeC
o / Cu) A VTR capstan motor rotation detection sensor using a multilayer film as a giant magnetoresistive element is introduced. This magnetic field sensor detects the change in the magnetic field from the multipolar magnetized rotating body, and as a result, detects the rotation speed in a non-contact manner. Therefore, in such a magnetic field sensor, it is very important to reduce the distance (gap) between the magnetoresistive film serving as the detection unit and the magnetized rotating body. Therefore, in this technical report,
A through hole is provided in an alumina substrate, and Ag is provided inside the through hole.
A structure is disclosed in which Pd is through-hole printed and fired to form an electrode lead-out portion on the back surface side of the substrate. Also, National Technical Report, Vol. 42, No. 4, 480-
With a magnetic field sensor using a Hall element introduced on page 488, in order to realize a surface mounting thickness of 200 μm or less, TAB (tape automatic bonding) mounting is performed on a substrate on which a magnetic field detecting element is formed, and Cu foil is used. Electrodes are drawn using leads. However, in such a conventional method, the process becomes complicated and causes a high cost.

Further, Journal of the Japan Society of Applied Magnetics, 1992,
Vol. On pages 16, 643 to 648, a conventional magnetic field detecting element in which a magnetic thin film is formed on a hard substrate,
It is described that since the magnetic characteristics of the magnetic film change due to the magnetoelastic effect due to unavoidable stress from the substrate and the protective film, various measures in consideration of the change are required. In particular, thermal stress is an important factor influencing the magnetic properties, and it is necessary to design a magnetic element with due consideration of the film forming temperature and the operating temperature. In addition, the magnetic characteristics of the magnetoresistive film often need to be finely optimized in accordance with various product specifications, resulting in a variety of products and complicated process management.

[0005]

SUMMARY OF THE INVENTION Under such circumstances, the present invention was devised, and an object of the present invention is to use an inexpensive substrate and form a magnetic film as a magnetic field detecting unit. A structure that does not have any protruding portion (protruding portion) that hinders magnetic field detection on the surface where it is made possible, and that a magnetoresistive element with excellent weather resistance can be manufactured by a simple process. Is to provide.
Further, the magnetic film formed on the flexible substrate is appropriately deformed and stress is applied to the magnetic film, and the magnetic characteristics can be easily optimized according to each product specification by utilizing the magnetoelastic effect. It is intended to provide a magnetoresistive element.

Furthermore, a so-called differential operation type magnetoresistive element in which at least two or more magnetic films are arranged at a predetermined interval, wherein the above-mentioned magnetic film interval is arbitrarily changed to obtain an optimum. An object of the present invention is to provide a magnetoresistive element capable of setting various measurement specifications.

[0007]

In order to solve such a problem, a magnetoresistive element according to the present invention comprises a magnetic film having a magnetoresistive effect for detecting a magnetic field, and a current flowing through the magnetic film. Are formed and arranged on a flexible substrate, respectively.

[0008] In a more preferred embodiment of the present invention,
The flexible substrate is composed of a polyimide film.

As a modification of the present invention, the magnetic film and the conductor electrode film are formed integrally from the same material.

[0010] In a more preferred embodiment of the present invention,
The magnetic film having the magnetoresistive effect is composed of a magnetic film exhibiting a giant magnetoresistive effect.

[0011] In a more preferred embodiment of the present invention,
The magnetic film having the magnetoresistance effect is configured to be a magnetic film exhibiting an antiferro (coupling) type giant magnetoresistance effect.

[0012] In a more preferred embodiment of the present invention,
The flexible base includes a curved portion formed by a bending process so that a magnetic film for detecting a magnetic field and an external connection portion formed on the conductor electrode film do not exist on the same plane. It is configured as follows.

[0013] In a more preferred embodiment of the present invention,
The flexible base is configured to include a curved portion formed by a bending process for arbitrarily changing magnetic properties by applying an external stress to the magnetic film.

Further, in the magnetoresistive element of the present invention, at least two or more magnetic films having a magnetoresistive effect for detecting a magnetic field, and a conductor electrode film for flowing a current through the magnetic film, respectively. , Formed on a flexible substrate.

[0015] In a more preferred embodiment of the present invention,
The at least two or more magnetic films are arranged at a predetermined interval, and are configured such that the magnetic substrate interval is arbitrarily changed by bending or bending the flexible base.

In a more preferred embodiment of the present invention,
A protective film formed by heat-treating a polyimide resin or a novolak resin is formed on the magnetic film.

Further, the magnetoresistive element of the present invention is configured to be used as a rotation detecting element in a more preferred embodiment.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a perspective view showing a magnetoresistive element 1 according to a preferred embodiment of the present invention.

As shown in FIG. 1, the magnetoresistive element 1 of the present invention comprises a magnetic film 15 having a magnetoresistive effect for detecting a magnetic field, and a magnetic film 15 on the surface of the same flexible substrate 10. And a conductor electrode film 2 for passing a current through the conductor electrode film 15
1 and 25 are arranged and formed, respectively. Here, the arrangement formation means a state where at least a part of each of the magnetic film 15 and the conductor electrode films 21 and 25 is formed on the flexible base 10.

The magnetic film 15 is usually formed in a predetermined pattern shape for detecting a magnetic field (in the example of FIG. 1, a linear pattern shape). 25, respectively. The conductor electrode films 21 and 25 also have a predetermined electrode pattern shape. Usually, one end of each of the conductor electrode films 21 and 25 has external connection portions (electrode pad portions) 21a and 25a as illustrated.
Is formed. Via the external connection portions 21a, 25a, the conductor electrode films 21, 25 and the external circuit are joined by soldering, wire bonding, or the like. FIG.
Shows an example of joining by soldering, and connection lines 32 and 36 are joined to external connection portions 21a and 25a by solders 31 and 35, respectively.

The magnetoresistive element of the present invention can of course be used without forcibly bending the flexible base 10 which forms the base thereof, but takes advantage of the characteristic that the base forming the base is the flexible base 10. By appropriately bending and using the flexible substrate 10, the range of application of the element and the effect to be exhibited become great.

In the example shown in FIG. 1, the flexible substrate 10 is curved using the flat auxiliary member 9 having the curved portions 9a, 9a, and the place where the magnetic film 15 is formed is It remains flat. In FIG. 3,
FIG. 2 is a plan view schematically showing a state before the flexible base 10 is bent as shown in FIG. By bending the flat magnetoresistive element shown in FIG. 3 along the line XX ′, the magnetoresistive element in the state shown in FIG. 1 is obtained.

FIG. 2 is a cross-sectional view showing a specific use situation of the magnetoresistive element shown in FIG. 1. The magnetic film 15 serving as a magnetic field detecting unit is, for example, a magnetic field generating unit 40 from the outside or a magnetic field change. And is used at a distance d from the ferromagnetic material 40 that causes

When the distance d increases, the magnetic field strength and the detection resolution decrease. Therefore, a projecting portion (hindering the detection of the magnetic field) is placed on the plane on which the pattern of the magnetic film 15 serving as the magnetic field detecting portion is formed. It is important that there is no convex part). As shown in FIGS. 1 and 2, the magnetoresistive effect element 1 of the present invention adopts a preferable mode in which a curved portion 11 is formed by bending a portion where the magnetic film 15 is not formed. Since no projecting portion (projecting portion) that hinders magnetic field detection is formed on the surface on which the film 15 is formed, the distance d can be extremely reduced.

As the flexible substrate 10 used in the present invention, it is preferable to use a thin and light one having excellent so-called flexibility, for example, a substrate similar to a plastic film widely used as a printed wiring board or the like. Can be used. More specifically, various materials known as plastic film materials, for example, polyimide, polyethylene terephthalate (PET), polypropylene (PP),
Teflon or the like is available. In particular, it is preferable to use a polyimide film having high heat resistance in consideration of bonding by solder at the end of the conductor electrode film.

The thickness of the flexible substrate 10 is not particularly limited, but is usually preferably from 1 to 200 μm, and particularly preferably from 10 to 150 μm.
If the thickness is less than 1 μm and the thickness is too thin, the strength as a substrate (substrate) may be insufficient. On the other hand, if the thickness exceeds 200 μm and becomes too thick, the flexibility becomes poor, and it may be difficult to perform a desired bending operation.

The flexible substrate 10 used in the present invention
Has no danger of being damaged even if it is thin. For this reason, a structure in which a magneto-sensitive element (magnetoresistive element) is formed on the front side and a magnetic field generating unit 40 or a ferromagnetic body 40 that causes a change in the magnetic field is arranged on the back side (hereinafter simply referred to as a “base 10”). Interposed arrangement structure ”). In this case, the thickness of the flexible base 10 is added to the distance d. However, since the thickness of the flexible base 10 is small, the base 10 has almost no adverse effect on the magnetic sensing effect. For example, when the distance d is 1 mm,
When the thickness of the flexible substrate 10 is 50 μm, their total value is only 1.05 mm at most. In particular, when corrosion resistance is required for the magnetoresistive effect element, the "base 10
The intervening arrangement structure "is preferable because the base 10 substantially serves as a protective film. In addition, it becomes possible to provide an external electrode that is greatly convex from the surface of the magneto-sensitive element. In order to make such a “base 10 interposed arrangement structure” effective, the flexible base 1
The thickness of 0 is preferably 200 μm or less, particularly preferably 75 μm or less. The “substrate 10 interposed arrangement structure” can be realized only by using the flexible substrate 10 of the present invention. In the case of a conventionally used non-flexible substrate such as glass, silicon, and ceramic, the manufacturing process is difficult. The possibility of breakage was high and it was difficult to realize.

Further, the plastic film used as the flexible substrate 10 is inexpensive as compared with an alumina substrate or a glass substrate, and is easy to cut or separate when forming an element form. There is also a merit of greatly contributing to the development.

The magnetic film 1 for detecting a magnetic field used in the present invention
Reference numeral 5 denotes a film having a magnetoresistive effect, which may have a single-layer structure or a multilayer structure. What is the magnetoresistance effect?
A phenomenon in which the electric resistance changes due to a change in the magnetic field. There is no problem even if the magnetic film 15 is a ferromagnetic film exhibiting an anisotropic magnetoresistive effect (anisotropic magnetoresistive film). It is preferable to use a giant magnetoresistive film (GMR film) capable of performing the following. The giant magnetoresistive film is a metal artificial lattice (Hiroshi Fujimori, Agne Technical Center, published in 1995) 3
As introduced on page 47, it is a multilayer film of a ferromagnetic film and a non-magnetic film, and it is known that the resistance changes due to a change in interface scattering of the multilayer film.

As the giant magnetoresistive film, an antiferro (coupling) type having a (ferromagnetic / non-magnetic conductor) structure,
(High coercivity ferromagnetic / non-magnetic conductor / low coercivity ferromagnetic) Inductive ferri (non-coupling) type, (semi-ferromagnetic /
It is roughly classified into a spin valve type having a (ferromagnetic material / non-magnetic conductor / ferromagnetic material) structure and a non-solid solution type granular type of Co / Ag system.

Each of these giant magnetoresistive films has a detectable magnetic field strength, that is, a saturation magnetic field strength of the magnetoresistive effect greatly differs depending on its structure and composition. For example, (F
e / Cr) type antiferro type, 10KOe or more, (C
oNiFe / Cu) antiferro type is 0.1 Oe
To 1 KOe, (NiFe / Cu / Co / Cu) -based ferrielectric ferritypes have about 5 to 20 Oe, (FeMn /
NiFe / Cu / NiFe) spin valve type, several Oe, and granular type from 100 Oe to 5K
Magnetic field detection up to about Oe is possible. The magnetic field sensitivity is obtained by dividing the maximum magnetoresistance change rate by the saturation magnetic field strength. Even if the maximum magnetoresistance change rate is large, the magnetic field sensitivity is poor when the saturation magnetic field is large. Conversely, even when the maximum magnetoresistance ratio is small, the magnetic field sensitivity is good when the saturation magnetic field is very small. For this reason, a basic system is selected from the various giant magnetoresistive films described above so that the highest magnetic field sensitivity is obtained depending on the magnetic field strength to be detected, and further, a composition system is changed and a fine structure is optimized and used. .

The resistance of the giant magnetoresistive film changes due to an in-plane parallel magnetic field. While the conventional anisotropic magnetoresistive film detects only the magnetic field in a specific direction in the plane, the giant magnetoresistive film basically does not depend on the direction as long as it is an in-plane magnetic field. However, among the giant magnetoresistive films, only the spin-valve type can detect a magnetic field in a specific direction as in the conventional anisotropic magnetoresistive film. In the present invention, since it is formed on a flexible substrate, it can be easily bent. However, when the bending process is performed, the magneto-sensitive composition portion which is a straight line in a plane may be deformed into a curve. For this reason, a structure that detects an in-plane magnetic field isotropically is preferable. In general, a magnetoresistive element for detecting rotation detects a magnetic field of about 50 Oe to 500 Oe, and thus is formed by combining an antiferro (coupling) type giant magnetoresistive film with a flexible substrate. Is particularly preferred.

Such a magnetoresistive film (magnetic film 15)
Is formed by a vacuum film forming method, for example, a vapor deposition method, a sputtering method, or the like. More specifically, after a magnetoresistive effect film is formed on the entire surface of the flexible substrate 10, it is patterned into a desired pattern shape to form a magnetic film 15 for detecting a magnetic field, and further joined to the magnetic film 15. Conductor electrode films 21 and 25 (electrodes) for passing a current are formed in a predetermined pattern. It is important that the conductor electrode films 21 and 25 have a smaller resistance than the magnetic film 15 which is a magnetoresistive film. For this reason, the conductor electrode films 21 and 25 are formed using a metal having high conductivity, for example, copper, gold, aluminum, or the like, to have a relatively thick specification, for example, a thickness of 0.3 to 5.0 μm. For forming the conductor electrode films 21 and 25, a wet film forming method can be used in addition to the vacuum film forming method. Also, first,
After forming the conductor electrode films 21 and 25, the magnetic film 1
5 (magnetoresistive film) may be formed. Further, as described above, the magnetic film 15 and the conductor electrode films 21 and
The magnetic film 15 and the conductor electrode films 21 and 25 may be integrally formed (formed) from the same material, instead of being composed of different materials individually. However, in this case, it is necessary to use the same material as long as the functions of the magnetic film 15 and the conductor electrode films 21 and 25 can be exhibited. The portion of the magnetic film is the magneto-sensitive pattern portion, and the portion of the conductor electrode film does not need to be the magneto-sensitive pattern portion. Therefore, in order to change the current density between the magneto-sensitive pattern portion and the electrode portion, the width of the electrode portion is designed to be wider than the width of the magneto-sensitive pattern portion. That is, by increasing the width of both ends of the pattern made of the same material, a function as a conductor electrode film can be provided. By using the same material, the magnetic film 1 which is a magnetically sensitive portion can be formed in one patterning process.
5 and the conductor electrode films 21 and 25 as electrode portions can be simultaneously formed, and extremely high productivity can be realized. This is similarly applied to all embodiments described later.

Since the magnetic film 15 (magnetoresistive film) is generally formed as a thin film having a thickness of 200 nm or less, corrosion resistance in a use environment often poses a problem. Therefore, it is preferable to provide a protective film at least above the magnetic film 15 to protect the magnetic layer 15 from the surrounding atmosphere. As the material of the protective film, it is particularly preferable to use a polyimide resin or a novolak resin. In particular, the flexible substrate 1
When a polyimide film is used as 0, it is preferable to use a polyimide resin as the protective film. Also,
The stress applied to the magnetic film 15 (magnetoresistive film) can be changed by changing the thickness of the resin layer formed as the protective film. Further, a thin film such as SiO ₂ or Al ₂ O ₃ can be provided under the resin layer formed as a protective film to protect the magnetic film 15 (magnetoresistive film) twice. Thereby, the function as the protective film is further strengthened. The polyimide resin or the novolak resin is thermally cured after being coated on the surface of the magnetic film 15 (for example, by using a spin coating method). The novolak resin has a structure close to bakelite by heat treatment and guarantees high corrosion resistance.

As described above, the magnetoresistive element 1 of the present invention comprises a magnetic film 15 having a magnetoresistive effect and a conductive electrode for flowing a current through the magnetic film 15 on a flexible substrate 10. Since the structure in which the films 21 and 25 are arranged and formed is adopted, bending deformation can be easily performed by applying an external force to the flexible base 10. That is, as shown in FIGS. 1 and 2, the portion (A) where the magnetic film 15 for detecting the magnetic field is formed is the conductor electrode film 2.
1 and 25 (for example, the external connection 21
a, 25a) The structure which is not on the same plane as (B) can be easily formed. Therefore, electrical connection with the outside can be made without performing a complicated through-hole process or TAB process of a substrate, which is conventionally performed, thereby achieving a significant cost reduction.

The magnetoresistance effect element 1 of the present invention described above.
Modifications are shown in FIG. 4 and FIG. FIG. 4 is a plan view schematically showing a state before the flexible base 10 is bent. FIG. 5 is a plan view of the flat magnetoresistive element shown in FIG. It is a perspective view of the magnetoresistive effect element formed by making each bend in two places of a Y 'line. In FIG. 5, the portion where the magnetic film 15 is formed constitutes a flat portion. The same effect as the magnetoresistive element shown in FIG. 1 can be obtained also in the magnetoresistive element having the two curved portions shown in FIG. In the drawings of the present invention, the same reference numerals indicate substantially the same members.

In the embodiment described above, the magnetic film 15
Has been described as an example, but depending on the type of external magnetic field to be detected, two or more magnetic films 15 (ferromagnetic film pattern portions) for magnetic field detection are provided as shown in FIG. In the example of the present invention, it is possible to use a so-called differential operation type for detecting a difference between the resistances. In FIG. 6, reference numeral 26 denotes a conductor electrode film, and reference numeral 2 denotes a conductive electrode film.
6a indicates an external connection portion (electrode pad portion).

Incidentally, the magnetoresistive film or the giant magnetoresistive multilayer film as the magnetic film 15 is composed of a ferromagnetic thin film as described above. The ferromagnetic material changes its magnetic anisotropy due to the magnetoelastic effect. The magnetoelastic effect anisotropy due to the product of the magnetostriction and the applied stress of the magnetic material greatly changes the magnetic anisotropy of the magnetic film, like other anisotropy, such as induced magnetic anisotropy and shape anisotropy. The degree of the magnetic anisotropy is one of important factors for determining the saturation magnetic field in the magnetoresistive film. Simply, the anisotropic magnetic field of the magnetic film becomes saturation magnetostriction in the magnetoresistance effect.

For this reason, when designing the magnetic film 15 in the magnetoresistive element of the present invention, when measuring a low magnetic field, a film with a small anisotropic magnetic field is used, and a magnetic field with a relatively large magnetic field is measured. Is required, it is preferable to use a film having a large anisotropic magnetic field. In a conventional magnetoresistive effect element, an anisotropic magnetic field is controlled by induced magnetic anisotropy and shape anisotropy in forming a magnetoresistive effect film (magnetic film). For this reason, after the formation or patterning of the magnetic film,
It was difficult to change the anisotropic magnetic field of the magnetic film.

On the other hand, the magnetoresistive effect element of the present invention easily adopts the structure of the thin film element formed on the flexible base as described above, so that the base (substrate) can be easily formed. ) Can be deformed, and as a result, an arbitrary stress can be externally applied to the magnetic film on the base. Moreover, by changing the size of the degree of deformation and the direction of the deformation (whether the substrate is in a convex state or a concave state),
The magnitude of the stress and the directions of the compressive and tensile stresses can also be arbitrarily changed. These specific configuration examples are shown in FIG.
To FIG. 9, respectively.

FIG. 7 is a perspective view of the plate-shaped magnetoresistive element shown in FIG. 3 in which a curved portion (convex shape) having a radius of curvature R is formed such that the ZZ 'line is the top of the curved portion. FIG. As can be clearly seen from the state shown in FIG. 7, the magnetic film 15 is also curved along a curved portion having a radius of curvature R,
As a result, stress is applied in the magnetic film 15. By arbitrarily changing the degree of the stress, that is, the degree of the radius of curvature R, the magnetic characteristics of the magnetic film 15 can be arbitrarily selected. This means that, even in the same element, the detected saturation magnetic field can be changed by changing the stress applied to the magnetic film 15 from the outside due to bending. Since the resistance change rate (Δρ) of the magnetic material due to the magnetic field is substantially determined by the structure, the material, and the like, setting the saturation magnetic field in accordance with the magnetic field strength (H) to be detected increases the magnetic field sensitivity (Δρ / H). ) Can be obtained. In the case of a magnetoresistive effect element having a small saturation magnetic field with respect to an external magnetic field, when the external magnetic field change (especially, decrease) occurs only for a short time in a short time in a small positional change, the pattern area of the magnetoresistive effect film is reduced. However, since it has a finite area instead of a point, it is often impossible to detect only the minimum pulse-like magnetic field portion, and the output as an element also decreases.

In the magnetoresistive element according to the present invention, since the above-mentioned curved portion can be formed, only the final stage of the production is changed in accordance with the product specifications (for example, the size of the curved portion is changed). In addition, it is possible to easily manufacture an element corresponding to a magnetic field intensity to be detected.

FIG. 8 shows that the flat magnetoresistive element shown in FIG. 4 is formed with a curved portion (convex shape) having a radius of curvature R such that the ZZ ′ line is the top of the curved portion. FIG. The magnetic film 15 is also curved along the curved portion having the radius of curvature R, and as a result, stress is applied to the inside of the magnetic film 15. FIG. 9 is a cross-sectional view in which a curved portion (concave shape) having a radius of curvature R is formed on the plate-shaped magnetoresistive effect element shown in FIG. 6 such that the line ZZ ′ is the bottom of the curved portion. . The magnetic film 15 is also curved along the curved portion having the radius of curvature R, and as a result, stress is applied to the magnetic films 15 and 15, respectively. The example shown in FIG. 9 is a so-called differential operation type magnetoresistive element provided with two magnetic films 15 and shows an embodiment as a rotation detection sensor for detecting the rotation speed of the rotating body 5. It is.

In a differential operation type magnetoresistive element having two or more magnetic films 15, it is necessary to optimize the pitch between a plurality of magnetic field detection units. For example, assuming that the pitch of the magnetic field generation of the object to be detected in the magnetized gear structure is P, the pitch between the magnetic field detection units of the detection element is P / 2 or P /
It becomes 4. Therefore, if the pitch of the magnetic field generating portions to be detected is different, it is necessary to manufacture elements of various specifications in accordance with the different pitches. For example, even with a rotation sensor using the same 48-pole magnetized gear as a magnetic field generating unit, the gear diameter (mm) is
Usually, there are 50, 67, 70, 89, and 96 types. On the other hand, in the magnetoresistance effect element of the present invention, the element itself can be easily bent,
It is possible to take measures only by changing the pitch between the magnetic field detection units. This situation is shown in FIGS.
This will be described with reference to FIG.

FIG. 10A is a plan view of a magnetoresistive element (differential operation type) according to the present invention, and is a view corresponding to FIG. FIG. 10B is a cross-sectional view of FIG. 10A, in which the conductor electrode film is omitted for easy understanding of the invention. FIG. 10A and FIG.
As shown in (b), when the element is not deformed, the pitch between the two magnetic films 15, 15 is (P1). This pitch (P1) can be easily changed. That is, as shown in FIGS. 10C and 10D, the magnetic film 1 serving as two magnetic field detection units
By bending or bending the flexible base 10 between 5 and 15, the pitch between the magnetic field detection units is set to (P2),
(P3) can be changed. In this case, the bending direction is possible regardless of whether the folded portion is concave or convex. Further, by further increasing the folding margin, even if the folding margin at the center portion is concave, the magnetic field detecting unit is further bent at the center between the central portion and the magnetic field detecting unit (magnetic film 15), so that the magnetic field generating unit Can be approached. Also, by folding the parts other than the magnetic field detection unit,
It is also possible to reduce the pitch of the magnetic field detector.

As described above, in the magnetoresistive element of the present invention, the element itself can be easily bent.
It is possible to change the pitch between the magnetic field detection units,
Only by changing the final stage of manufacturing (for example, changing the degree of bending or folding) in accordance with the product specifications, it is possible to easily manufacture an element that matches the detection target.

[0048]

EXAMPLES Hereinafter, the present invention will be described in more detail by showing specific examples of the present invention.

A polyimide film manufactured by Ube Industries, Ltd., Upilex (12.5 μm, 75 μm,
And 125 μm) were prepared, and these films were used as the flexible substrate (substrate) of the present invention. Also,
As a comparative example, a glass substrate having a diameter of 3 inches and a thickness of 0.7 mm was also used as a base for comparison. On each of these substrates (substrates), giant magnetoresistive films (magnetic films 15) as shown in Table 1 below were formed using an ion beam sputtering apparatus. The notation of the multilayer structure in Table 1 indicates thickness-composition in the order of film formation. Although not shown in Table 1, for example, “50 ° −Ta /
(10 ° -NiFe / 5 ° -Cu) × 10 ”means that 50 ° Ta is firstly stacked, and then 10 ° NiFe alloy and 5% Cu are stacked in order of 10 layers, each having a total thickness of 200 ° and 21 °.
1 shows a magnetic multilayer film composed of layers.

[0050]

[Table 1] The targets used in forming the giant magnetoresistive film were each a target composition having a purity of 99.9% or more. After evacuation was performed to a final pressure of 4 × 10 ⁻⁷ Torr, argon gas was introduced, and the film was formed. Vacuum degree is 1.4
× 10 ^-4 Torr. In addition, only the induction ferri-type multilayer film having the film structure C shown in Table 1 (Table 1: Film C) was formed by an ultra-high vacuum deposition apparatus. Each film was formed by water cooling of the substrate. After a multilayer giant magnetoresistive film was formed on the entire surface of the substrate, the photoresist was exposed to light through a mask and developed to form a desired magnetic film pattern, and then unnecessary portions were removed by an ion milling device. Thereafter, a portion other than the conductor electrode film (including a magnetic film pattern serving as a magnetic field detecting portion) was covered with a polyimide resist, and a copper film as a conductor electrode film was formed to a thickness of 3 μm by electroplating. Electroless nickel plating of 0.2 μm on this copper film
Electroless gold plating was formed thereon to a thickness of 0.5 μm. After these plating, 300 ° C in vacuum
For one hour to cure the polyimide resist, and then separated into individual magnetoresistive elements.

A tin-plated copper wire was joined to an external connection portion (electrode pad portion) at the end of the conductor electrode film of the magnetoresistive element by soldering. This joint was raised about 1 mm from the surface of the substrate. Further, when the tin-plated copper wire is routed, the copper wire may be separated up to a position distant from the surface of the substrate by a maximum of about 3 mm.

Such a magnetoresistive element with a conductor electrode film was attached to various auxiliary members (Teflon) to produce element samples having various modifications as shown in Table 2 below.

[0053]

[Table 2] An element sample having each of these modifications was mounted on a 48 mm-polarized 96 mm diameter gear by 1 mm, 3 mm and 4 mm.
The voltage change was measured at a position of mm while applying a current of 5 to 50 mA. Table 3 shows the measurement results.

[0054]

[Table 3]

[0055]

The effects of the present invention are clear from the above results. That is, in the magnetoresistive element of the present invention, a magnetic film having a magnetoresistive effect for detecting a magnetic field, and a conductor electrode film for flowing a current through the magnetic film are each provided on a flexible base. , It is possible to deform the element itself. Therefore, a structure is possible in which no projecting portion (projecting portion) that hinders the detection of the magnetic field is formed on the surface of the magnetic film serving as the magnetic field detecting portion on which the magnetic film is formed. Furthermore, a magnetoresistive element having excellent weather resistance can be manufactured by a simple process. Further, the magnetic film formed on the flexible substrate is appropriately deformed and stress is applied to the magnetic film, and the magnetic characteristics can be easily optimized according to each product specification by utilizing the magnetoelastic effect. . Furthermore, in a so-called differential-operation-type detection magnetoresistive element in which at least two or more magnetic films are arranged at predetermined intervals, the optimum measurement specification can be set by arbitrarily changing the magnetic film interval.

[Brief description of the drawings]

FIG. 1 is a perspective view of a magnetoresistive element according to a preferred embodiment of the present invention.

FIG. 2 is a cross-sectional view showing a specific usage state of the magnetoresistance effect element.

FIG. 3 is a plan view schematically showing a state before bending a flexible base.

FIG. 4 is a plan view schematically showing a state before bending a flexible base.

5 is a plan view of the magnetoresistive effect element shown in FIG.
It is a perspective view of the magnetoresistive effect element formed by making it curve at each of two places of -X 'line and YY' line.

FIG. 6 is a magnetic film for detecting a magnetic field (a ferromagnetic film pattern portion).
Is a plan view of a so-called differential operation type magnetoresistive element for detecting two or more resistors and detecting a difference between their resistances.

FIG. 7 is a plan view of the magnetoresistive element shown in FIG.
It is the perspective view which formed the curved part (convex shape) of curvature radius R so that the ZZ 'line might become the top part of a curved part.

FIG. 8 is a plan view of the magnetoresistive element shown in FIG.
It is the perspective view which formed the curved part (convex shape) of curvature radius R so that the ZZ 'line might become the top part of a curved part.

9 is a plan view of the magnetoresistive element shown in FIG.
It is sectional drawing which formed the curved part (concave shape) of curvature radius R so that ZZ 'line might become the bottom part of a curved part.

10A is a plan view of a magnetoresistive effect element (differential operation type) of the present invention, FIG. 10B is a cross-sectional view of FIG.
(C) and (d) are cross-sectional views after the element is deformed.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 ... Flexible base material 15 ... Magnetic film 21, 25, 26 ... Conductor electrode film

Claims (12)

[Claims] 1. A magnetic film having a magnetoresistive effect for detecting a magnetic field and a conductor electrode film for flowing a current through the magnetic film are respectively formed on a flexible substrate. A magnetoresistive effect element characterized in that: 2. The magnetoresistive element according to claim 1, wherein said flexible substrate is a polyimide film. 3. The magnetic film and the conductor electrode film,
3. The magnetoresistance effect element according to claim 1, wherein the magnetoresistance effect element is formed integrally from the same material. 4. The magnetoresistance effect element according to claim 1, wherein said magnetic film having a magnetoresistance effect is a magnetic film exhibiting a giant magnetoresistance effect. 5. The magnetoresistive element according to claim 1, wherein the magnetic film having a magnetoresistive effect is a magnetic film exhibiting an antiferro (coupling) type giant magnetoresistive effect. 6. The flexible substrate is formed by a bending process such that a magnetic film for detecting a magnetic field and an external connection portion formed on a conductor electrode film do not exist on the same plane. The magnetoresistive element according to any one of claims 1 to 5, comprising a portion. 7. The flexible substrate according to claim 1, further comprising a curved portion formed by a bending process for arbitrarily changing magnetic properties by applying an external stress to the magnetic film. The magnetoresistance effect element according to any one of the above. 8. At least two or more magnetic films having a magnetoresistive effect for detecting a magnetic field, and a conductor electrode film for flowing a current through the magnetic films, respectively, on a flexible base, A magnetoresistive element, which is arranged and formed. 9. The magnetic film according to claim 8, wherein the at least two or more magnetic films are arranged at a predetermined interval, and the interval between the magnetic films is arbitrarily changed by bending or bending the flexible base. 3. The magnetoresistive effect element according to 1. 10. The magnetoresistive element according to claim 8, wherein the magnetic film and the conductor electrode film are integrally formed from the same material. 11. The magnetoresistive element according to claim 1, wherein a protective film formed by heat-treating a polyimide resin or a novolak resin is formed on the magnetic film. 12. The magnetoresistive element according to claim 1, which is used as an element for detecting rotation.