JP2002270918A - Magnetic impedance device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a magnetic impedance(MI) device which can be improved in density, reduced in size, and bettered in mounting properties by a method wherein lower conductive thin films are formed at certain intervals on an insulating board and at an angle inclining relative to the prescribed direction of the board, upper conductive thin films are formed at the same intervals with the lower conductive think films on a magnetic thin film, and the upper and lower conductive thin films are connected each other so as to be used as a bias coil. SOLUTION: Lower conductive thin films 3 are formed on an insulating board 2, upper conductive films 6 and recesses 5 are provided to a magnetic thin film 4, the conductive thin films 3 and 6 are connected each other through the recesses 5 with a tapere 7 so as to form a coil, so that a coil-integrated MI device 1 can be obtained. A tapering angle θ is set at 45 deg. or below (preferably 45 deg.), and this magnetic impedance device can be protected against a disconnection or a contact failure.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic impedance (hereinafter referred to as "MI") element using a conductive thin film as a coil.
It can be used for sensors.

[0002]

2. Description of the Related Art Conventionally, an MI element has two structures, a magnetic wire type as shown in FIG. 4 and a magnetic thin film type as shown in FIG. In these, when a high-frequency current (I _ac ) or a pulse current (I _p ) is applied, the magnitude of impedance greatly changes due to an external magnetic field (Hex).
The I effect is used.

In Japanese Patent Application Laid-Open No. 11-109006, M
As a structure for forming the I sensor, a first conductive thin film and a second conductive thin film are interposed between a substrate made of a non-magnetic material and a magnetic thin film formed on the substrate with an insulator interposed therebetween. In some cases, a plurality of thin film conductors are wound in the longitudinal direction of a magnetic thin film as a bias coil and a negative feedback coil.

[0006] The graph shown in FIG. 6 is a magnetic field-impedance change rate. This MI effect is caused by an external magnetic field (Hex).
In order to exhibit the characteristic of being symmetric with respect to the positive and negative sides, a DC bias magnetic field was applied by a coil or a magnet to shift the magnetic field-impedance change rate and used as a sensor.

In the graph shown in FIG. 6, the point b of the graph is shifted to Hex = 0 by applying a DC bias magnetic field, and the linear characteristic portion of the magnetic field [Hex] change and the impedance change is changed in the range of a. Used as a sensor.

[0006]

Magnetic wire type MI element THE INVENTION An object to provide a process, in but a high sensitivity is used as the sensor, the coil winding and mounting technologies, there is a problem to be troublesome. There is also a problem that miniaturization is very difficult.

[0007] thin film MI elements, implementations it is possible to facilitate the substrate wiring technique, there is a problem that is difficult miniaturization it is necessary to use a coil or magnet.

Further, in the structure of the MI sensor as disclosed in Japanese Patent Application Laid-Open No. H11-109006, when patterning a coil on a magnetic thin film, there is a problem that the wiring is disconnected or a contact failure occurs.

[Means for Solving the Problems]

In order to solve the above-mentioned problems, the present invention is to connect a conductive thin film provided on an insulating substrate and a magnetic thin film to form a bias coil, thereby enabling downsizing. This is because a conductive thin film is formed on an insulating substrate at a constant inclination angle with respect to a predetermined direction of the substrate and at a constant interval, and a magnetic thin film is also formed at the same interval as the lower conductive thin film. The problem is solved by providing a MI element capable of high density by connecting the lower and upper conductive thin films and using the coil as a coil.

According to the first aspect of the present invention, a bias coil is wound around a magnetic thin film for keeping the magnetic orientation constant, and in the MI element using the MI effect, the lower conductive film is provided at a constant inclination angle and a constant interval with respect to a predetermined direction of the insulating substrate. A conductive thin film is formed, an upper conductive thin film is formed on a magnetic thin film at a fixed inclination angle and a fixed interval with respect to a predetermined direction of the thin film, and the upper and lower conductive thin films are connected to form a coil. Claim 2 is an MI device, wherein the magnetic thin film is provided with a concave portion along the longitudinal direction, and the upper conductive thin film and the lower conductive thin film in the concave portion are connected. Item 1. The magneto-impedance element according to item 1, wherein the problem of disconnection and poor contact is solved by increasing the density.

[0011] According to claim 3, wherein the magnetic thin film, FeCo
Amorphous film or the B and CoNbZr and CoFeNi as the main raw material, a thin film monolayer MI element according to claim 1, characterized in that the crystal system magnetic film, in claim 4, and the lower conductive layer 2. A cross section connected to the upper conductive film is tapered.
It is a thin film type single-layer MI element described in the above.

According to a fifth aspect of the present invention, there is provided the thin-film single-layer MI element according to the fourth aspect, wherein θ is 45 degrees or less, where θ is the taper angle of the taper. disconnection by integrating the coil as a thin film,
Prevents poor contact.

[0013]

FIG. 1 is a perspective view of the structure and manufacturing method. FIG. 2 is a sectional view of a main part of a conductive thin film serving as a bias coil. FIG. 3 is a perspective view showing a completed MI element.

Reference numeral 1 denotes an MI element, and 2 is an insulating substrate, on which a lower conductive thin film 3 is formed as a solid film for wiring at a predetermined inclination angle and a predetermined interval with respect to a predetermined direction of the substrate.
Reference numeral 4 denotes an amorphous film made of a magnetic material, which is mainly made of FeCoB, CoNbZr, or CoFeNi, or a magnetic thin film 4 in which the magnetic orientation of a crystalline magnetic film is adjusted. 5 is
Concave portions provided at both ends in the longitudinal direction of the magnetic thin film 4. The upper conductive thin film 6 is formed on the upper surface of the magnetic thin film 4 for wiring at a fixed inclination angle and a fixed interval with respect to a predetermined direction of the thin film. The coil is formed by connecting the lower conductive thin film 3 and the upper conductive thin film 6, and is combined with the magnetic thin film to form the MI element 1.

A first embodiment of the present invention will be described with reference to FIGS. 1, 2 and 3. FIG. A pattern is formed on the insulating substrate 2 in advance by using the lower conductive thin film 3 as a wiring. At this time, patterning at a constant inclination angle and distance for a given direction of the insulating substrate 2.

Next, a film is formed by a photolithography technique, and a film is formed by adjusting the magnetic orientation so as to be in the width direction of the magnetic thin film 4 by a sputtering method in a magnetic field, and the lower conductive film 3 is formed on both sides of the magnetic thin film 4 in the longitudinal direction. The recesses 5 are formed at the same intervals as in FIG.

Next, the upper conductive thin film 6 is connected to the concave portion 5 on the patterned magnetic thin film 4 by a photolithography technique at a predetermined inclination angle and a predetermined interval with respect to a predetermined direction of the magnetic thin film 4 for wiring. A film is formed so as to form a pattern. Then, the upper and lower conductive thin films 4 and 6 are connected by the concave portion 5.

The conductive thin film used as the coil is preferably made of copper, and the upper conductive thin film 6 requires the magnetic thin film 3 to have a thickness of 2 to 3 μm. Since it is difficult to connect the lower conductive thin film 3 and the upper conductive thin film 6, the cross section is tapered. This can be formed by over-etching, and is used when a photolithography technique is used. If the taper angle is θ, over-etching is performed until the taper angle becomes 45 degrees or less. Preferably, θ is 45 degrees.

By the above-described method, it is possible to manufacture a structure in which a conductive thin film is formed in a coil shape on the insulating substrate 2 using the magnetic thin film 4 whose magnetic orientation is adjusted. The high-frequency current (I) is applied to the magnetic thin film 4 formed by the above method.
_ac ) or the flow of the pulse current (I _P ) causes the magnitude of the impedance to be greatly changed by the external magnetic field (H _ex ). (MI effect)

By applying a DC bias magnetic field by the coil pattern wiring made of the conductive thin film, Hex = 0 is shifted to a point b in a graph showing a symmetrical impedance change rate and a magnetic field as shown in the graph of FIG. By using the straight line portion in the range of (1), it can be used as a thin film integrated type MI sensor.

A second embodiment of the present invention will be described. The structure is also the same as that of the first embodiment. The difference is that a structure is used in which a conductive thin film is formed in a coil shape similar to that of the first embodiment using a metal mask without using photolithography technology. it is possible.

As shown in the first and second embodiments,
The pattern can be formed by photolithography or film formation using a metal mask. It is also effective to provide a step without providing the taper 7.

The magnetic direction of the magnetic thin film 4 can be adjusted by using a sputtering method in a magnetic field. However, when the magnetic thin film 4 is manufactured by ordinary vapor deposition, sputtering, or plating, the magnetic direction is adjusted by annealing in a magnetic field after film formation. Requires a process.

Although not specifically shown as a third embodiment,
The magnetic thin film 4 provided in the same manner as in the first embodiment and the second embodiment is a coil-integrated type made of a conductive thin film. 1 can be connected by a wiring electrode made of a conductive film, and the detection sensitivity can be further increased by increasing the resistance.

The structure of that time, the lower conductive thin film 3 and the upper conductive thin film 6 as a coil, is integrated in a thin magnetic thin film 4, be MI element 1 is not described in particular since the above.

Further, if the plurality of magnetic thin films 4 are individually parallel, they may be zigzag and may be connected by a conductive thin film to increase the detection sensitivity.
As described above, the detection sensitivity is improved by connecting the MI element 1 to the conductive film for wiring.

[0027]

In the MI element, it is conventionally necessary to wind a coil later or provide a magnet. However, a concave portion is provided in the magnetic thin film and the cross section is tapered to form wiring at the time of coil patterning. As a result, the MI element is more easily integrated with the coil,
The structure as a sensor is advantageous for miniaturization.

Since everything can be formed by patterning, it is advantageous in terms of mounting, and circuit connection (mounting) of ICs and the like is possible.
It is also possible to increase the density.

[0029]

[Brief description of the drawings]

FIG. 1 is a perspective view showing a first embodiment of the present invention.

FIG. 2 is a sectional view of a main part of the first embodiment of the present invention.

FIG. 3 shows a completed perspective view of the first embodiment of the present invention.

FIG. 4 is a diagram showing a conventional wire-type MI element.

FIG. 5 is a diagram showing a conventional single-layer MI element.

FIG. 6 is a diagram showing a magnetic field and a rate of change in impedance of a conventional MI element, showing a bias to be shifted for use as an MI sensor and a region used as a sensor.

[Explanation of symbols]

··· · MI element 2 ··· Insulating substrate 3 ··· Lower thin conductive film 4 ··· Magnetic thin film 5 ··· Recess 6 ··· Upper thin conductive film 7 ···· Taper θ・ Taper angle a ・ ・ ・ Linear area using MI sensor b ・ ・ ・ Bias point for using linear area to use MI sensor

Claims (5)

[Claims] In a magneto-impedance element using a magneto-impedance effect by winding a bias coil around a magnetic thin film for maintaining a constant magnetic orientation, a lower conductive film is formed at a predetermined inclination angle and a predetermined interval with respect to a predetermined direction of an insulating substrate. Forming a thin film, forming an upper conductive thin film on the magnetic thin film at a predetermined inclination angle and a predetermined interval with respect to a predetermined direction of the thin film, and connecting the upper and lower conductive thin films to form a coil; Impedance element. 2. The magnetic thin film according to claim 1, wherein a concave portion is provided along the longitudinal direction, and an upper conductive thin film and a lower conductive thin film in the concave portion are connected. Magnetic impedance element. 3. The magnetic thin film is made of FeCoB or CoNbZ.
an amorphous film mainly composed of r or CoFeNi, or
2. The magneto-impedance element according to claim 1, wherein the magneto-impedance element is a crystalline magnetic film. 4. The magneto-impedance element according to claim 1, wherein a cross section where the lower conductive film and the upper conductive film are connected is tapered. 5. The method according to claim 1, wherein said taper angle is θ.
The magneto-impedance element according to claim 4, wherein θ is 45 degrees or less.