JP2003264393A - Electromagnetic wave shield and device equipped therewith - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To permit the efficient absorption of an electromagnetic wave in a wide frequency band, in an electromagnetic shield capable of preventing the malfunction of an electronic device or the like. <P>SOLUTION: The electromagnetic wave shield 21, for example, is formed of a base plate 21a and a plurality of clusters 21b provided on the base plate 21a. A plurality of magnetic dots 21c, formed by pattern forming by a lithographic process or the like and having substantially the same configuration, are arrayed uniformly on respective clusters 21b. The magnetic dot 21c is constituted so as to be capable of controlling a resonance frequency in a wide frequency band by changing the configuration thereof in each cluster 21b. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electromagnetic wave shield and an apparatus provided with the same, and more particularly, to an electromagnetic wave shield having an electromagnetic wave shield effect and capable of preventing malfunction of electronic devices and the like. It relates to a composite device provided.

[0002]

2. Description of the Related Art Usually, for example, a device having an electronic function (electronic device) is accompanied by movement of electrons when functioning. Therefore, electromagnetic waves are leaked around the device. The leaked electromagnetic wave induces a flow of electrons in the conductor. In the future, as electronic devices become smaller in size, individual functions will be realized by a smaller number of electrons as the size becomes smaller. Then, the flow of electrons induced by the leaked electromagnetic waves causes a malfunction of the electronic device.

FIG. 7 shows an example of a conventional composite device (apparatus). For example, in the case of a composite device in which a plurality of electronic devices (in this example, the magnetic device 2 and the semiconductor devices 3 and 4) are mounted on the substrate 1,
When functioning, mutual interference by the electromagnetic wave 5 occurs between the devices 2, 3 and 4. This causes a malfunction of each device 2, 3, 4.

In order to prevent the malfunction of the device as described above, it is necessary to prevent the leakage of electromagnetic waves from the device having an electronic or electromagnetic function. It is also important to shield the electromagnetic waves from the surrounding environment and reduce the electromagnetic waves applied to the device.

In recent years, the frequency of electromagnetic waves generated from various devices has been extremely high, reaching the GHz order.
For this reason, much research is being conducted to shield high-frequency electromagnetic waves (for example, the Autumn Meeting of the Japan Institute of Metals 2001 (129th) Convention, page 386,
"Refer to" Electromagnetic Wave Absorption Properties of Fe-Mo-O Nanocomposite Particles ").

[0006]

In the above research, a film containing magnetic particles (magnetic powder) is formed as an electromagnetic wave shield. When a high frequency electromagnetic wave is applied to the magnetic particles, the magnetic particles cause ferromagnetic resonance. as a result,
It absorbs the energy of electromagnetic waves. At this time, the frequency of the electromagnetic wave to be absorbed substantially depends on the size of the magnetic particles. Therefore, if the magnetic particles have a uniform size, electromagnetic waves having a frequency near the resonance frequency are absorbed, but electromagnetic waves having other frequencies are not absorbed.

In an actual electromagnetic wave shield, magnetic particles of different sizes having various resonance frequencies are mixed. As a result, it is necessary to lower the frequency dependence of the absorption characteristics of electromagnetic waves to absorb electromagnetic waves in a wide frequency band.
In the above research, iron powder (magnetic particles) was used as a raw material, and the size variation (dispersion) of the iron powder was used.
It absorbs electromagnetic waves in a wide frequency band.

However, in the above research, there is a limit to increase the dispersion of iron powder size. Therefore, there is a limit to absorbing electromagnetic waves in a wide frequency band.

The present invention has been made to solve the above problems, and an object thereof is to efficiently absorb electromagnetic waves in a wide frequency band and to suppress mutual interference of electromagnetic waves between devices. An object of the present invention is to provide an electromagnetic wave shield and a device equipped with the same.

[0010]

In order to achieve the above-mentioned object, an electromagnetic wave shield of the present invention, which shields an electric field or a magnetic field, has a pattern formed on a substrate having an arbitrary shape. It is characterized by arranging a plurality of formed magnetic bodies.

Further, in the apparatus provided with the electromagnetic wave shield of the present invention, a device having an electronic or electromagnetic function and a substrate provided so as to cover at least a part of the device are provided. And an electromagnetic wave shield formed by arranging a plurality of patterned magnetic bodies each having an arbitrary shape.

Further, in the composite type device provided with the electromagnetic wave shield of the present invention, a plurality of devices provided on the same substrate and any substrate provided at least between the plurality of devices are provided. An electromagnetic wave shield formed by arranging a plurality of magnetic bodies each having a shape and having a pattern formed.

According to the electromagnetic wave shield of the present invention and the device provided with the same, the shape of the magnetic material to be patterned can be freely changed. This makes it possible to control the resonance frequency of the magnetic material in a wide frequency band.

Here, the ferromagnetic resonance frequency is, to be exact,
It depends on the magnitude of magnetic anisotropy of the magnetic particles. Therefore, simply increasing the dispersion of the size of the magnetic particles,
It is difficult to obtain an electromagnetic wave shield that functions in a wide frequency band. In particular, in order to increase the resonance frequency, it is necessary to increase the magnetic anisotropy of the magnetic particles. For that purpose, it is necessary to have strong shape anisotropy of the magnetic particles, that is, to use needle-shaped magnetic particles.

As described above, by using a magnetic material having various shapes and increasing the dispersion of the magnetic anisotropy of the magnetic material, an electromagnetic wave shield capable of shielding an electromagnetic wave in a wide frequency band can be obtained. it can. That is, the electromagnetic wave shield is constituted by an array of minute magnetic bodies patterned by a lithography process or the like. The shape of the magnetic body patterned by a lithography process or the like can be freely changed, and the shape can be easily controlled. Therefore, it is possible to control the resonance frequency of the magnetic body in a wide frequency band.

In particular, the electromagnetic wave shield is divided into a plurality of areas, and minute magnetic bodies having substantially the same shape are uniformly arranged in each area, and the shape of the magnetic body is changed between adjacent areas. As a result, the electromagnetic wave shield comes to have various resonance frequencies.

Further, by directing the magnetic anisotropy of the minute magnetic material in various directions, it becomes possible to efficiently shield electromagnetic waves from various directions.

Further, in order to increase the efficiency of the electromagnetic wave shield, it is preferable to form a minute magnetic substance on the metal layer or the magnetic layer.

Further, stacking a plurality of electromagnetic wave shields with an insulating layer interposed therebetween is very effective in increasing the shield efficiency.

By covering at least a part of the periphery of a device having an electronic or electromagnetic function with the electromagnetic wave shield of the present invention, the influence of the electromagnetic wave on other devices can be suppressed, or the device can prevent electromagnetic waves from the environment. You can prevent being affected.

Further, by providing the electromagnetic wave shield of the present invention between a plurality of devices mounted on the same substrate, it is possible to obtain a composite device which functions effectively without interfering with each other.

The electromagnetic wave shield of the present invention can also be used to prevent the influence of electromagnetic waves from peripheral devices on devices that function in the body, such as cardiac pacemakers.

[0023]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows an example of the configuration of a composite device (composite type device) according to an embodiment of the present invention.

This composite device has, for example, a substrate 11
A plurality of electronic devices (in this example, the minute magnetic device 12 and the minute semiconductor devices 13 and 14) having an electronic or electromagnetic function are mounted thereon. Then, the electromagnetic wave shield 21 of the present invention is provided so as to cover at least a part of the periphery of each of the devices 12, 13, and 14 (or at least the electromagnetic wave shield 21 has at least each of the devices 12, 13). , 14
Provided between each other). This makes it possible to reduce the electromagnetic waves leaking from the devices 12, 13, and 14. Therefore, each of the above devices 12, 13, 1
It is possible to prevent mutual interference between the four and prevent other electronic devices from malfunctioning.

Particularly, when the electromagnetic wave shield 21 is provided so as to surround each of the devices 12, 13, and 14, the electromagnetic wave applied from the surrounding environment,
It is also possible to reduce the influence on the devices 12, 13, 14 described above.

The electromagnetic wave shield 21 of the present invention, which is suitable for use in the above-mentioned composite device, will be described below.

2 and 3 show examples of the structure of the electromagnetic wave shield 21. 2A shows the overall structure of the electromagnetic wave shield 21, and FIG. 2B shows a part of the electromagnetic wave shield 21 in an enlarged manner. Further, FIG. 3 shows a part of the electromagnetic wave shield 21 in cross section.

The electromagnetic wave shield 21 is shown in FIG.
As shown in (a) and FIG. 3, it is an aggregate of a plurality of regions called clusters 21b provided on the base 21a.

As shown in FIGS. 2B and 3, for example, each of the clusters 21b has a plurality of magnetic dots (fine magnetic bodies) 21c which are patterned by a lithography process and have substantially the same shape. , Are arranged uniformly.

In this example, the shape of the magnetic dots 21c is shown as a rectangular parallelepiped. The shape of the minute magnetic dot 21c, which is patterned by a lithography process or the like, can be freely changed, and the shape can be easily controlled. Therefore, magnetic dot 2
It is possible to control the resonance frequency of 1c in a wide frequency band.

FIG. 4 shows the relationship between the width of the magnetic dot 21c and the resonance frequency. Here, magnetic dots 2
Fe is used as the material of 1c, the length of the magnetic dot (Fe dot) 21c is 8 μm, and the thickness of the Fe dot 21c is 0.1 μm, 0.2 μm, and 0.5 μm, respectively.
It shows the result when.

As shown in the figure, the resonance frequency gradually increases as the width of the Fe dot 21c decreases.
Further, when the Fe dot 21c is thick, a higher resonance frequency can be obtained.

As is clear from this figure, the Fe dots 21
20-30G from low frequency by changing the width of c
It is possible to choose a resonance frequency over a wide range up to a high frequency of Hz. Therefore, each cluster 21
In b, by changing the shape of the Fe dots 21c, the resonance frequency of the entire shield can be dispersed in a very wide band, that is, the electromagnetic wave shield 21 can have various resonance frequencies (wide band property).

Here, by including the magnetic dots 21c of various shapes in each cluster 21b, the above-mentioned wide band property can be obtained. However, in order to obtain the magnetic dots 21c arranged with high regularity and high density,
Magnetic dots 21 included in each cluster 21b
It is desirable that the shape of c be the same and that the shape of the magnetic dots 21c be changed for each cluster 21b. By arranging the magnetic dots 21c at a high density, the efficiency of the electromagnetic wave shield 21 is improved.

In this embodiment, Fe is used as the material of the magnetic dots 21c, but other magnetic materials can be used. In order to increase the shield efficiency, it is preferable to use a material having a high magnetic permeability. For example, Ni-F
It is effective to use a high magnetic permeability material such as e.

Particularly, when importance is attached to the magnetic permeability in the high frequency band, a laminated body of a magnetic metal and an insulator or a laminated body of a magnetic metal and a semiconductor is used as the material of the magnetic dot 21c. Good. In this case, the eddy current loss is reduced and high magnetic permeability can be obtained in the high frequency band.

In order to obtain a high resonance frequency, it is necessary to use a material having a high saturation magnetic flux density for the magnetic dots 21c. Examples of materials having a high saturation magnetic flux density include Fe and Fe—Co based alloys.

FIG. 5 shows an example of the easy magnetization direction of the cluster 21b. In the electromagnetic shield 21,
For example, as shown in the figure, when the easy magnetization direction 31 of the cluster 21b is oriented in various directions, electromagnetic waves applied from various directions can be efficiently shielded. Also in this case, it is preferable that the magnetic dots 21c in the same cluster 21b have substantially the same shape and direction.

When the magnetic dots 21c have a rectangular parallelepiped shape as in this embodiment, the magnetic dots 21c have a substantially uniaxial magnetic anisotropy when the width of the magnetic dots 21c is narrow. The magnetic anisotropy does not necessarily have to be uniaxial,
Uniaxial magnetic anisotropy is advantageous for obtaining high magnetic anisotropy, that is, for obtaining high resonance frequency.

As described above, it becomes possible to obtain the electromagnetic wave shield 21 in which resonance absorption occurs in a wide frequency band by the arrangement of the minute magnetic dots 21c patterned by the lithography process or the like. As a result, it is possible to realize the high-performance electromagnetic wave shield 21 that can be applied to the minute electronic devices 12, 13, and 14 in the composite device.

As described above, the shape of the magnetic dots to be patterned can be freely changed. That is, by an array of a plurality of magnetic dots patterned with an arbitrary shape by a lithography process or the like,
It is designed to form an electromagnetic wave shield. As a result, the resonance frequency of the magnetic dots can be controlled in a wide frequency band. Therefore, it is possible to efficiently absorb electromagnetic waves in a wide frequency band, and in particular, in compounding electronic devices, it is possible to suppress mutual interference of electromagnetic waves between devices.

In the above embodiment, directly
Although the case where the magnetic dots are formed on the substrate has been described as an example, the magnetic dots 21c may be formed on the metal layer 22 made of a magnetic layer as shown in FIG. 6, for example. In this case, the electromagnetic wave shield 2 with higher efficiency
1'can be obtained.

Further, in order to enhance the shield efficiency, when shielding is performed not only for the magnetic field component of the electromagnetic wave but also for the electric field component, it is formed on a metal layer (not shown) made of a non-magnetic metal. It is preferable to form magnetic dots.

Further, in the above-mentioned composite device, in order to further improve the shield efficiency, it is desirable that the electromagnetic wave shields 21 and 21 'are laminated a plurality of times via an insulating layer (not shown).

Furthermore, the electromagnetic wave shields 21 and 21 'of the present invention can be used not only for use in a composite device but also for shielding a small single device. It can also be used in equipment other than devices. For example, by using the electromagnetic wave shields 21 and 21 'of the present invention, it is possible to easily solve the problem that a device that functions in the body such as a cardiac pacemaker is affected by electromagnetic waves from surrounding devices.

In addition, the present invention is not limited to the above (each) embodiment, and can be variously modified at the stage of implementation without departing from the scope of the invention. Further, the above (each) embodiment includes inventions at various stages, and various inventions can be extracted by appropriately combining a plurality of disclosed constituent elements. For example,
(Each) Even if some constituent elements are deleted from all the constituent elements shown in the embodiment, the problem (at least one) described in the section of the problem to be solved by the invention can be solved, and The effect mentioned in the column (at least one of)
When the above is obtained, the configuration in which the constituent requirements are deleted can be extracted as the invention.

[0048]

As described above in detail, according to the present invention, an electromagnetic wave shield capable of efficiently absorbing electromagnetic waves in a wide frequency band and suppressing mutual interference of electromagnetic waves between devices, and an electromagnetic wave shield provided therewith. It is possible to provide a device.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an example of a composite device according to an embodiment of the present invention.

FIG. 2 is a plan view showing a configuration example of an electromagnetic wave shield provided in the composite device shown in FIG.

3 is a cross-sectional view showing a configuration example of the electromagnetic wave shield shown in FIG.

FIG. 4 is a characteristic diagram shown for explaining the relationship between the width of magnetic dots and the resonance frequency in the electromagnetic wave shield of the present invention.

FIG. 5 is a plan view showing the easy magnetization direction of clusters in the electromagnetic wave shield of the present invention.

FIG. 6 is a cross-sectional view showing another configuration example of the electromagnetic wave shield according to the present invention.

FIG. 7 is shown for explaining the conventional technology and its problems,
The block diagram of a composite device.

[Explanation of symbols]

11 ... Substrate 12 ... Magnetic device 13, 14 ... Semiconductor device 21,21 '... electromagnetic wave shield 21a ... Base 21b ... cluster 21c ... magnetic dot 22 ... Metal layer 31 ... Easy magnetization direction

Claims (20)

[Claims] 1. An electromagnetic wave shield for shielding an electric field or a magnetic field, characterized in that a plurality of magnetic bodies each having a pattern and having an arbitrary shape are arranged on a substrate. 2. The plurality of magnetic bodies are divided into a plurality of regions, and each region has a substantially identical shape and is uniformly arranged.
Electromagnetic wave shield described in. 3. The electromagnetic wave shield according to claim 2, wherein the plurality of magnetic bodies have different shapes in adjacent regions. 4. The electromagnetic wave shield according to claim 3, wherein the plurality of magnetic bodies have substantially the same magnetic anisotropy direction. 5. The electromagnetic wave shield according to claim 3, wherein the magnetic anisotropy directions of the plurality of magnetic bodies are changed in respective regions. 6. The electromagnetic wave shield according to claim 4, wherein the plurality of magnetic bodies have a substantially uniaxial magnetic anisotropy. 7. The electromagnetic wave shield according to claim 1, wherein the plurality of magnetic bodies are formed on a metal layer provided on the base body. 8. The electromagnetic wave shield according to claim 1, wherein the plurality of magnetic bodies are formed on a magnetic layer provided on the base. 9. The electromagnetic wave shield according to claim 1, wherein the electromagnetic wave shields are laminated via an insulating layer. 10. A device having an electronic or electromagnetic function, and a plurality of magnetic patterns formed in an arbitrary shape on a base body so as to cover at least a part of the device. An apparatus comprising: an electromagnetic wave shield formed by arranging bodies. 11. Arrangement of a plurality of devices provided on the same substrate, and a plurality of magnetic bodies, which are provided between at least the plurality of devices and are patterned on a substrate, the magnetic bodies having an arbitrary shape. A composite type device comprising: 12. The plurality of magnetic bodies in the electromagnetic wave shield are divided into a plurality of regions, and each region has a substantially same shape and is uniformly arranged. The device according to claim 10 or 11. 13. The apparatus according to claim 12, wherein the plurality of magnetic bodies have different shapes in adjacent regions. 14. The apparatus according to claim 13, wherein the plurality of magnetic bodies in the electromagnetic wave shield have substantially the same magnetic anisotropy direction. 15. The apparatus according to claim 13, wherein the plurality of magnetic bodies change the direction of magnetic anisotropy in each region. 16. The apparatus according to claim 14, wherein the plurality of magnetic bodies in the electromagnetic wave shield have a substantially uniaxial magnetic anisotropy. 17. The device according to claim 10, wherein the plurality of magnetic bodies in the electromagnetic wave shield are formed on a metal layer provided on the base body. 18. The apparatus according to claim 10, wherein the plurality of magnetic bodies in the electromagnetic wave shield are formed on a magnetic layer provided on the base body. 19. The electromagnetic wave shield is laminated via an insulating layer.
1. The device according to 1. 20. The apparatus according to claim 11, wherein at least one of the plurality of devices has an electronic or electromagnetic function.