JPH07191118A - Magnetic sensor - Google Patents

Abstract

PURPOSE:To provide such a magnetic sensor in a layered structure manufactured by using a semiconductor machining technique as being capable of easily flattening the backing (lower layer) of a plane ring core. CONSTITUTION:A whole sensor is made up in a three-layer structure of the first wiring layer 1 in which an excitation line 1a and a signal line 1b are formed, a ring core 2 and the second wiring layer 3 in which an excitation line 3a and a signal line 3b are formed corresponding to the formation pattern of the first wiring layer 1 so that flattening can be performed at the same time when the excitation line 1a and the signal line 1b are formed in the lower layer of the ring core 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic sensor used to measure, for example, geomagnetism.

[0002]

2. Description of the Related Art Conventionally, as a magnetic sensor of this type, a band-shaped magnetic film is wound around a groove of a ring body to form a ring core, and an exciting wire is wound around the ring core in a spiral shape. There is a structure in which a signal line is wound in a direction orthogonal to a magnetic field perpendicular to the ring core.

However, according to the magnetic sensor having such a structure, the thickness of the wound film becomes non-uniform because the thickness of the insulating layer of the band-shaped magnetic film itself constituting the ring core varies. This causes the magnetic detection characteristics to deteriorate, and it is difficult to obtain orthogonality with the ring core when winding the signal line, and there are problems that the detection accuracy decreases due to the uneven winding. It was

In order to solve the above problems, semiconductor processing technology is used to stack two layers of a signal line and an excitation line on a substrate, and a planar ring core is formed on this layer with an insulating layer interposed therebetween. There is proposed a magnetic sensor having a structure in which two layers of an excitation line and a signal line are formed on top of that, and the upper and lower excitation lines and the signal line are mutually connected. (JP-A-2-213781).

[0005]

By the way, in the technique of the above-mentioned publication, the surface of the underlayer (lower layer) forming the planar ring core (magnetic film) is a flat surface having the highest possible flatness. Is desirable. This is because when the ring core is formed on the uneven surface, magnetostriction occurs at the stepped portion of the unevenness, and the magnetic characteristics are deteriorated.

Therefore, in order to improve accuracy in this type of laminated magnetic sensor, it is necessary to perform flattening processing on the signal line and the excitation line in the lower layer of the ring core. Therefore, it is difficult to realize a perfect plane by the flattening process.

That is, since two layers of the signal line and the excitation line formed in the shape of sleepers are laminated in the lower layer of the ring core, a flattening process is performed twice for each of the layers. Are required, and inevitably the irregularities on the surface forming the ring core become large.

Further, the flattening process requires stacking of insulating layers having a thickness of several μm, but the order of stacking is a relatively thick thin film stacking process in the semiconductor processing technology, and therefore the number of stacking layers is small. However, there is a problem that the alignment error increases as the number increases. Furthermore, as the number of stacked layers increases, it becomes difficult to contact the signal lines in the upper and lower layers or the excitations with each other, which lowers the reliability thereof. Further, the larger the number of stacked layers, the more complicated the process becomes and the higher the cost is. There is a problem such as a factor leading to a decrease in reliability.

The present invention has been made in view of such circumstances, and is a laminated magnetic sensor manufactured by utilizing a semiconductor processing technique, and has a structure in which the base (lower layer) of a planar ring core can be easily planarized. An object of the present invention is to provide a magnetic sensor of.

[0010]

In order to achieve the above object, the magnetic sensor of the present invention is, as shown in FIGS. 1 to 3 corresponding to an embodiment, provided on an insulating layer laminated on a substrate or an insulating substrate S. First wirings on which a plurality of excitation lines 1a ... 1a and signal lines 1b ... 1b having a predetermined shape are formed alternately along a predetermined circumference and at predetermined intervals. The layer 1 and the insulating layer 4 in the region corresponding to the circumference on the layer 1
A planar ring core 2 formed by sandwiching it, an insulating layer 5 formed on the ring core 2, and an insulating layer 5 on the insulating layer 5.
The first wiring layer 1 is provided with the second wiring layer 3 in which the excitation lines 3a ... 3a and the signal lines 3b ... 3b are formed in correspondence with the respective line formation patterns of the first wiring layer 1. The excitation line 1a and the excitation line 3a, and the signal line 1b and the signal line 3b are connected to each other between the and the second wiring layer 3, and the excitation coil and the signal line coil are formed around the ring core 2 as a whole. It is characterized by

[0011]

Since the entire sensor has a three-layer structure (excluding the insulating layer), the excitation line 1a and the signal line 1b, which are the base of the planar ring core 2, are formed in the layer 1 of the same level. Accordingly, the flattening process at the time of forming the signal line 1b can be performed in the same process. As a result, the flattening process of the base of the ring core 2 is required only once.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. 1A and 1B are structural views of an essential part of an embodiment of the present invention, in which FIG. 1A is a longitudinal sectional view and FIG. Note that (a) shows a cross section taken along line XX of (b).

The magnetic sensor as a whole has a first wiring layer 1 laminated on a glass substrate S, and a planar ring core (magnetic film) 2 and a second wiring layer 3 on this layer, respectively.
It has a three-layer structure (excluding the insulating layer) in which insulating layers 4 and 5 are sandwiched.

As shown in the plan view of FIG. 2, the first wiring layer 1 has L-shaped excitation lines 1a ... 1a and signal lines 1b.
1b are formed alternately along the circumference corresponding to the formation region of the ring core 2 and at a predetermined distance from each other.

Further, as shown in the plan view of FIG. 3, the second wiring layer 3 has an excitation line whose L-shape is opposite to the lines 1a and 1b of the first wiring layer 1 described above. 3a and 3a and the signal lines 3b and 3b are respectively the lines 1a and 1a of the first wiring layer 1, respectively.
It is formed at a position opposed to 1b with the ring core 2 interposed therebetween.

Then, the excitation lines 1a ... 1a of the first wiring layer
.. and 3a of the second wiring layer are connected to each other at the contact portion C, as shown in the schematic view of FIG. 4 (a). Also, as shown in FIG. 4 (b),
The signal lines 1b..1b and 3b..3b are also connected in the same manner, and as a whole, an excitation coil and a signal line coil are formed around the ring core 2. In addition, each coil has an excitation coil electrode (pad).
6 and the signal line (detection) coil electrode 7 are connected (see FIG. 3).

Next, the manufacturing procedure of the magnetic sensor having the above structure will be described below with reference to FIGS. In addition,
5 and 6 are AA and B of FIGS. 2 and 3, respectively.
It is a figure which shows typically the shape of a B-arrow cross section.

First, as shown in each of FIGS. 5 (a) and 6 (a), a metal film 1c of Al or the like is formed on the glass substrate S by, for example, 2 μm.
A film having a thickness of about m is formed, and the metal film 1c is processed by a method such as ion milling to obtain the excitation lines 1a..1a and the signal lines 1b..1b having the pattern shown in FIG. Each figure
(b)].

After that, in order to reduce the unevenness of the excitation line 1a and the signal line 1b, an insulating layer 4a of SiO ₂ or the like is laminated [each figure (c)] and then flattened [each figure (d) )].
The flattening process includes, for example, thinly forming a Ni-Fe film.
Photolithography → patterning by ion milling → SiO ₂ film formation → lift-off. If a higher degree of flatness is required, a flattening process such as laminating an insulating layer such as SiO ₂ and then etching back by ion milling is performed after the above process.

After the above flattening process is completed, the insulating layer 4
A permalloy film having a film thickness of, for example, about 4 μm is formed thereon,
Next, after patterning the permalloy film to obtain a planar ring core 2, for example, SiO _{2 is formed} to a film thickness of 3 μm.
Then, the insulating layer 5 is formed by forming a film with m (FIGS. (e) and (f)). After that, the insulating layer 5 is patterned (opening a window) to open the contact hole H shown in the schematic view of FIG. 4 [Fig. (G)]. Although the contact hole on the signal line side is not shown, the patterning of the opening is similar to that on the excitation line side (see FIG. 5 (g)).

Then, a metal film of Al or the like is formed to have a film thickness of, for example, about 2 μm, the metal film is processed by a method such as ion milling, and the excitation lines 3a ... Of the pattern shown in FIG. By forming 3a and the signal lines 3b ... 3b [(h) in each figure], the magnetic sensor having the three-layer structure shown in FIG. 1 is obtained.

The material for forming the excitation line and the signal line may be Al, or other metal such as Au, Cu or Pt. Further, as the substrate, another insulating substrate such as a quartz substrate may be adopted, or a substrate obtained by laminating an insulating layer on a Si substrate may be used.

Here, in the above embodiment, each excitation line 1
Although the a and 3a and the signal lines 1b and 3b are shaped toward the center of the circle of the ring core 2, the excitation line and the signal line are not limited to this, and the excitation line and the signal line are inclined with respect to the normal line of the ring core 2. It may be wiring.

Further, in the above embodiments, the excitation lines 1a, 3
Although the width of a is wider than that of the signal lines 1b and 3b, for example, when the number of turns of the ring core 2 is increased, the widths of the excitation line and the signal line may be approximately the same. Further, the patterns and patterns of the excitation line and the signal line are not particularly limited as long as the excitation coil and the signal line coil can be formed around the ring core 2 respectively.

[0025]

As described above, according to the present invention,
Since the entire sensor has a three-layer structure and the excitation line and the signal line, which are the lower layers of the planar ring core, are formed on the same level layer, the flattening process for forming the excitation line and the signal line is only required once. This makes it possible to finish the surface on which the ring core is formed into a flat surface having a higher degree of flatness than in the past. As a result, the magnetic characteristics are improved. Moreover, both the excitation coil and the signal line coil can be formed in the vicinity of the ring core, and the sensor sensitivity and efficiency are improved.

Further, since the number of insulating layers to be laminated at the time of the flattening process is small, it is possible to reduce the alignment error and improve the reliability of mutual contact between the wiring layers above and below the ring core. Furthermore, the realization of the three-layer structure has the advantages that the structure is simplified, downsizing and higher sensitivity can be achieved, and the process is simplified to improve yield and throughput.

[Brief description of drawings]

FIG. 1 is a structural view of an embodiment of the present invention, (a) is a cross-sectional view of a main part,
(b) is a partial plan view

FIG. 2 is a plan view showing a pattern of a first wiring layer 1 of the embodiment.

FIG. 3 is a plan view showing a pattern of the second wiring layer 3 in the same manner.

FIG. 4 is a schematic diagram conceptually showing the contact between the first and second wiring layers of the embodiment of the present invention.

FIG. 5 is a diagram illustrating a manufacturing procedure according to an embodiment of the present invention.

FIG. 6 is an explanatory diagram of the same manufacturing procedure.

[Explanation of symbols]

 S glass substrate 1 first wiring layer 1a ·· 1a excitation line 1b ·· 1b signal line 2 planar ring core (magnetic film) 3 second wiring layer 3a ·· 3a excitation line 3b ·· 3b signal line 4, 5 Insulation layer C contact part

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Megumi Shinada 1 Nishinokyo Kuwabara-cho, Nakagyo-ku, Kyoto Prefecture Kyoto Sanjo Factory Sanjo Factory (72) Inventor Yoichi Fujiyama 1 Kinohara Kuwahara-cho Nishinokyo, Kyoto City Kyoto Prefecture Shimadzu Sanjo Factory (72) Inventor Tatsuya Kumonaka 1 Nishinokyo Kuwabaracho, Nakagyo-ku, Kyoto Prefecture Kyoto Prefecture Shimazu Corporation Sanjo Factory

Claims (1)

[Claims] 1. A plurality of excitation lines and signal lines having a predetermined shape are alternately arranged along a predetermined circumference on an insulating layer or an insulating substrate laminated on a substrate, and at predetermined intervals. The formed first wiring layer, the planar ring core formed on this layer with the insulating layer sandwiched in a region corresponding to the circumference, the insulating layer formed on the ring core, and the insulating layer A second wiring layer on which an excitation line and a signal line are formed corresponding to each line formation pattern of the first wiring layer is provided on the upper side, and the first wiring layer and the second wiring layer are provided. A magnetic sensor in which the excitation line and the excitation line, the signal line and the signal line are connected to each other, and the excitation coil and the signal line coil are formed around the ring core as a whole.