JP4611698B2 - EMC countermeasure member and EMC countermeasure method - Google Patents

Description

  The present invention relates to an EMC countermeasure member and an EMC countermeasure method using the same.

In recent years, as electronic devices such as mobile phones, personal computers, and digital cameras have become smaller and lighter, electronic components such as CPUs, LSIs, and peripheral semiconductors mounted in these electronic devices have been increased in density and integration. In addition, high-density mounting of electronic components and the like on a printed wiring board is progressing. In addition, the frequency to be handled is increasing for higher performance of electronic devices. Along with this, there are problems such as failure, malfunction and malfunction of electronic equipment due to radiation noise radiated from electronic components or conduction noise transmitted through the wiring circuit of the printed circuit board.
For this reason, as defined in Non-Patent Document 1, both EMI (Electro Magnetic Interference) measures to prevent one's own influence and EMS (Electro Magnetic Susceptibility) measures to reduce the influence from others are taken. EMC (Electro Magnetic Compatibility) measures that have been combined have been demanded.

As an EMS countermeasure method for suppressing the influence from others, generally, there is a method of reflecting radiation noise propagating through space using a metal plate as an electromagnetic shielding material.
In addition, an electromagnetic wave interference suppressor composed of an insulating soft magnetic layer containing a soft magnetic powder and an organic binder and a conductive support is provided on an electronic component, etc., and shields against electromagnetic wave transmission. There is known a method in which the conductive support is shielded and the insulating soft magnetic layer does not promote electromagnetic coupling against reflection (Patent Document 1).
In addition to shielding with the metal plate described above, the EMI countermeasure method for preventing oneself from affecting others is to cover the bus line of the information processing apparatus with a composite magnetic material composed of soft magnetic powder and an organic binder. It is known to take measures (Patent Document 2).

  Shielding by reflection using a conductive shielding material such as a metal plate is effective for leakage of radiation noise among EMC countermeasures, but radiation noise reflected and scattered by this shielding material is present inside the electronic equipment. There is a problem that it fills up and promotes electromagnetic interference, and there is a problem that electromagnetic interference occurs between a plurality of printed boards installed in an electronic device, and its use range is limited.

  The method described in Patent Document 1 is effective for suppressing radiation noise from a distant place and radiation noise from an electronic component or the like by a conductive support. Among them, no consideration is given to conduction noise propagating through a conductor such as an electronic component.

The composite magnetic material described in Patent Document 2 has an insulating soft magnetic material layer similar to the electromagnetic wave interference suppressor described in Patent Document 1, and is a radiation radiated from a cable or the like as an antenna among EMI countermeasures. It is intended to take measures against noise and does not suppress conduction noise. Conducted noise is caused by fluctuations in the power supply voltage due to switching operations, etc., and affects the functions of electronic devices. In particular, signal waveforms are disturbed due to mismatched characteristic impedance of wiring circuits or reflected at mismatched points. Etc. are settled and resonate to generate radiation noise and affect others. For this reason, in EMI countermeasures, it is required to suppress conduction noise before conduction noise generated from an electronic component or the like becomes radiation noise.
Furthermore, as an EMS countermeasure, there is a demand for an EMC member and a countermeasure method thereof that can also suppress radiation noise particularly from a distance.
“Absorption and shielding of electromagnetic waves”, Nikkei Technical Books, January 10, 1989, p. 377 Japanese Patent Laid-Open No. 7-212079 JP 9-312489 A

  Accordingly, an object of the present invention is to provide an EMC countermeasure member having a conduction noise suppression function and a radiation noise suppression function, and an EMC countermeasure method using the same.

That is, the EMC countermeasure member of the present invention is magnetically deposited on a binder having a shear modulus of 1 × 10 ³ to 1 × 10 ⁷ Pa by physical vapor deposition. and transmission noise suppressing layer containing a dispersed body in forming a fixed combination, possess a radiation noise suppressing layer containing a binder and an electromagnetic wave absorbing material, the thickness of the conductive noise suppressing layer, 0.005 to 0. and it is characterized in 3μm der Rukoto.

Here, the magnetic body is preferably a metallic soft magnetic body containing one or more elements selected from the group consisting of iron, cobalt and nickel.
The binder is preferably an organic polymer.

In addition, the EMC countermeasure method of the present invention is such that the EMC countermeasure member of the present invention is placed near the wiring circuit in the electronic component or the wiring circuit on the substrate, and the conductive noise suppression layer is on the conductor or substrate of the wiring circuit in the electronic component. It arrange | positions so that it may couple | bond with the conductor of this wiring circuit electromagnetically.
Here, it is desirable that the distance between the conductor of the wiring circuit in the electronic component or the conductor of the wiring circuit on the substrate and the conduction noise suppression layer is 0.8 mm or less.

EMC countermeasure member of the present invention, by physical vapor deposition, the shear modulus during physical vapor deposition binder is ^{1 × 10 3 ~1 × 10 7} Pa, by depositing a magnetic substance, a magnetic substance and dispersed in binding a fixed combination transmission noise suppressing layer; because it has a radiation noise suppressing layer containing a binder and an electromagnetic wave absorbing material, it combines the two electromagnetic noise suppression function of the radiation noise suppressing function and transmission noise suppressing function It will be.

Here, if the magnetic material is a metal-based soft magnetic material containing one or more elements selected from the group consisting of iron, cobalt, and nickel, an oxide-based magnetic material that exhibits magnetic properties due to crystal anisotropy Unlike the magnetic body and the nitride-based magnetic body, heating for recrystallization is not necessary, so the manufacturing process of the EMC countermeasure member is not troublesome, and a lightweight organic polymer having flexibility is used as a binder. Can be used as
And if the said binder is an organic polymer, it will be flexible and can be used as a high intensity | strength EMC countermeasure member, and it is excellent in the adhesiveness and followable | trackability to an electronic component etc.
Further, the thickness of the conductive noise suppressing layer, 0.005 to der Runode, and further improve transmission noise suppressing effect can be achieved thinning and weight reduction.

In addition, the EMC countermeasure method of the present invention is such that the EMC countermeasure member of the present invention is placed near the wiring circuit in the electronic component or the wiring circuit on the substrate, and the conductive noise suppression layer is on the conductor or substrate of the wiring circuit in the electronic component. As a countermeasure for EMS, it is possible to suppress radiation noise from far away, and as an EMI countermeasure, conducted noise generated from electronic parts, etc. The conduction noise can be suppressed before the noise becomes radiation noise.
Furthermore, if the distance between the conductor of the wiring circuit in the electronic component or the conductor of the wiring circuit on the substrate and the conduction noise suppression layer is 0.8 mm or less and electromagnetically coupled, the conduction noise is efficiently suppressed. be able to.

The present invention will be described in detail below.
<EMC countermeasure material>
The EMC countermeasure member of the present invention comprises a conductive noise suppression layer in which a magnetic material is dispersed in a binder having a shear modulus of 1 × 10 ³ to 1 × 10 ⁷ Pa during physical vapor deposition by physical vapor deposition. A radiation noise suppressing layer containing a binder and an electromagnetic wave absorbing material.

As such an EMC countermeasure member, for example, as shown in FIG. 1, a skin layer 4 containing a binder 2 and an electromagnetic wave absorbing material 3 dispersed therein and having no electromagnetic wave absorbing material 3 is formed. A magnetic material dispersed in a part of the binder 2 of the skin layer 4 of the radiation noise suppression layer 5 by physical vapor deposition, and a part of the binder 2 of the skin layer 4 and the magnetic substance The EMC countermeasure member 1 which has the conductive noise suppression layer 6 formed by integrating the. In addition, as shown in FIG. 2, an EMC countermeasure member body 10 in which a radiation noise suppression layer 7 containing a binder 2 and an electromagnetic wave absorber 3 is further laminated on the surface of the conduction noise suppression layer 6; as shown in FIG. In addition, the EMC countermeasure member 20 in which two EMC countermeasure members 1 are laminated may be used.
Furthermore, an adhesion function for disposing the EMC countermeasure member in the electronic device or near the wiring circuit on the substrate may be provided on the surface of the EMC countermeasure member.

The EMC countermeasure member of the present invention preferably has a loss power ratio (also referred to as a power loss value) at 1 GHz, which is an index of a conduction noise suppression effect, of 0.3 to 0.95, preferably 0.4 to 0.95. More preferably.
Here, the loss power ratio is a comprehensive index of the reflection / transmission characteristics of the conduction noise suppression function, and is obtained by the following equation and takes a value of 0 to 1. The loss power ratio can be obtained by the following equation from changes in transmission characteristics S ₁₁ (reflection attenuation) and S ₂₁ (transmission attenuation).
Loss power ratio (P _loss / P _in ) = 1− (| Γ | ² + | T | ² )
Here, S ₁₁ = 20 log | Γ |, S ₂₁ = 20 log | T |, Γ is a reflection coefficient, and T is a transmission coefficient.

In order to sufficiently exhibit the conduction noise suppressing effect, the loss power ratio is preferably 0.3 or more. If the loss power ratio is smaller than 0.3, it cannot be said that the conductive noise is sufficiently suppressed. Furthermore, the loss power ratio is preferably 0.4 or more. If the loss power ratio is 0.4 or more, there is a sufficient conduction noise suppression effect. With the current technology, it has not been possible to obtain a loss power ratio exceeding 0.95 at 1 GHz.
In order to set the loss power ratio of the EMC countermeasure member to 0.3 to 0.95, the binder and the magnetic material are formed at the nanometer level by performing physical vapor deposition at high energy when producing the EMC countermeasure member. This can be achieved by selecting the physical vapor deposition conditions and the magnetic material vapor deposition amount as appropriate based on integration with atoms.

The EMC countermeasure member of the present invention preferably has a mutual decoupling rate at 1 GHz, which is an index of the radiation noise suppression effect, of -1 dB or more, and more preferably -2 dB or more. The internal decoupling rate at 1 GHz is preferably −1 dB or more, and more preferably −2 dB or more.
The mutual decoupling rate is an amount of how much the coupling between two printed circuit boards or devices is attenuated by mounting the EMC countermeasure member. The internal decoupling rate is the amount by which the coupling between transmission lines or the same printed circuit board is attenuated by mounting an EMC countermeasure member (Shigeru Takeda, “Current Status of IEC Standardization of Noise Suppression Sheets”) , 131st Study Group Material, Japan Society of Applied Magnetics, July 4, 2003, p. 33-36).

(Conduction noise suppression layer)
As shown in FIG. 5 which is a schematic diagram of the high-resolution transmission electron microscope image of FIG. 4 and the electron microscope image, the conduction noise suppression layer 6 physically applies a magnetic substance to the skin layer 4 on the surface of the radiation noise suppression layer 5. It is a layer formed by vapor deposition, and is formed by dispersing and integrating the physically vapor-deposited magnetic material in the binder 2 in an atomic state without forming a homogeneous film.

  The conduction noise suppression layer 6 has a crystal lattice 11 in which magnetic atoms with a few angstrom intervals are arranged as a very small crystal, and a portion that is recognized as being in a flake state and a magnetic material within a very small range. It consists of a portion where only the non-existent binder 2 is observed and a portion where the magnetic substance atoms 13 are not crystallized but are dispersed and observed. In other words, the grain boundary where the magnetic substance is present as a fine particle having a clear crystal structure is not observed, and it has a complex heterostructure (heterogeneous / asymmetric structure) in which the magnetic substance and the binder are integrated at the nanometer level. is doing.

  The thickness of the conduction noise suppression layer 6 is the depth of penetration of the magnetic atoms into the surface of the radiation noise suppression layer 5 and depends on the vapor deposition mass of the magnetic material, the binder material, the physical vapor deposition conditions, etc. It becomes about 1.5 to 3.0 times the deposition thickness of the magnetic material. Here, the vapor deposition thickness of the magnetic material means a film thickness when the magnetic material is physically vapor-deposited on a hard base material that does not allow magnetic atoms to enter.

  By setting the thickness of the conduction noise suppression layer 6 to 0.005 μm or more, the magnetic material atoms can be dispersed and integrated with the binder 2 and have a large magnetic loss characteristic in a high frequency region derived from shape anisotropy. This is considered to be a sufficient conduction noise suppression effect. On the other hand, when the thickness of the conduction noise suppression layer 6 exceeds 0.3 μm, a homogeneous magnetic film is formed through a clear crystal structure, and returns to the bulk magnetic body, thereby reducing the shape anisotropy, The conduction noise suppression effect is also reduced and is not effective. Therefore, the thickness of the conduction noise suppression layer is more preferably 0.3 μm or less.

The specific resistance of the conduction noise suppression layer 6 is several times to several hundred times larger than the value calculated from the specific resistance of the bulk magnetic metal, but the surface resistance is about 10 ¹ to 10 ³ Ω / cm ^2. Therefore, it is important to take sufficient insulation measures when the conductive noise suppression layer 6 is disposed near the conductor.

(Skin layer)
The skin layer 4 in the present invention is a layer formed of only the binder 2 in the radiation noise suppressing layer 5 containing the electromagnetic wave absorbing material 3 and formed on the surface of the radiation noise suppressing layer 5 and without the electromagnetic wave absorbing material 3. It is.

  The average thickness of the skin layer 4 may be sufficient to form the above-described conductive noise suppression layer 6 having a thickness of 0.005 to 0.3 μm, specifically 0.1 to 300 μm. Preferably there is. If the average thickness of the skin layer 4 is less than 0.1 μm, a part of the electromagnetic wave absorbing material 3 may be exposed on the surface of the skin layer 4, and the portion where the electromagnetic wave absorbing material 3 is exposed suppresses conduction noise. Since the layer 6 is not formed uniformly, the conduction noise suppression effect is reduced. When the skin layer 4 is thicker than 300 μm, since the electromagnetic wave absorbing material 3 is not dispersed in the radiation noise suppression layer 5, the radiation noise suppression effect may be reduced.

(Binder)
The binder 2 is not particularly limited, but polyolefin, polyamide, polyester, polyether, polyketone, polyimide, polyurethane, polysiloxane, phenolic resin, epoxy resin, acrylic resin, polyacrylate, vinyl chloride resin, chlorination Resins such as polyethylene; diene rubbers such as natural rubber, isoprene rubber, butadiene rubber and styrene butadiene rubber; and organic polymers such as non-diene rubbers such as butyl rubber, ethylene propylene rubber, urethane rubber and silicone rubber . These may be thermoplastic, thermosetting, or uncured products thereof. Further, it may be a modified product such as the above-mentioned resin or rubber, a mixture, or a copolymer.

Among them, as the binder 2, a material having a low shear elastic modulus is used in the physical vapor deposition of a magnetic material described later in terms of ease of entry of magnetic substance atoms into the binder 2. Specifically, the shear modulus of the binder 2 at the time of physical vapor deposition of the magnetic material is 1 × 10 ³ to 1 × 10 ⁷ Pa. If necessary, the binder can be heated to, for example, 100 to 300 ° C. in order to obtain a desired shear modulus, but it is necessary to heat to a temperature at which decomposition and evaporation do not occur.
The binder 2 is preferably silicone rubber, urethane rubber, acrylic rubber, or ethylene propylene rubber having flexibility and rubber elasticity from the viewpoint of adhesion that affects the effect of suppressing conduction noise. The shear modulus of 2 is preferably 1 × 10 ³ to 1 × 10 ⁶ Pa.

The following methods are known as methods for measuring the shear modulus.
(1) The tensile elastic modulus is obtained from the relationship between the tensile stress and strain defined in JIS K7113, and the shear elastic modulus is obtained from the following formula based on this.
Shear modulus = Tensile modulus / (2 x (1 + Poisson's ratio))
Here, the value of 2 × (1 + Poisson's ratio) is approximately 2.6 to 3.0 from a rigid polymer to a rubbery elastic body.
(2) Using a viscoelasticity measuring device capable of grasping the temperature characteristics, the shear modulus is measured with the test mode set to the shear mode.
(3) Using a viscoelasticity measuring device, in the test mode tension mode, the storage elastic modulus G ′ and the loss elastic modulus G ″ are measured, the complex elastic modulus G * is obtained from the following formula, and the complex elastic modulus is determined as the tensile elastic modulus. As described above, the shear modulus is obtained from the above formula.
G * = √ ((G ′) ² + (G ″) ² )
The shear elastic modulus in the present invention is a value measured using a solid analyzer RSA-II manufactured by Rheometric Scientific as a viscoelasticity measuring device in a shear mode under a measurement frequency of 1 Hz.

  Here, in order to lower the shear modulus of the binder 2, a gel-like, paste-like, or oil-like component can be added. Examples thereof include silicone oil, paraffin wax, polyethylene wax, higher alcohol, and higher fatty acid ester. When such a binder 2 is used, since the radiation noise suppression layer 5 itself exhibits adhesiveness, when the EMC countermeasure member is disposed on the LSI, the peripheral semiconductor, or the flexible wiring board, the adhesive layer and the adhesive layer are provided. Even if it does not provide, it can arrange. However, when a gel-like, paste-like or oil-like component is added, these components may bleed from the radiation noise suppression layer 5. This contaminates LSI and peripheral semiconductors, forms an insulating film, and causes poor contact of electronic components, so care must be taken in blending.

The binder 2 is preferably one having a high shear elastic modulus after physical vapor deposition of the magnetic material from the viewpoint of maintaining the above-described heterostructure and maintaining the effect of suppressing conduction noise. By increasing the shear modulus of the binder 2 after physical vapor deposition of the magnetic material, it is possible to reliably prevent the nanometer-level magnetic material atoms or clusters from aggregating and crystallizing to grow into fine particles. Specifically, the thing of 1 * 10 < ⁷ > Pa or more is preferable in the temperature range where EMC countermeasure member is used. In order to obtain a desired shear modulus, it is preferable to crosslink the binder after physical vapor deposition of the magnetic material. In this respect, as the binder, a thermosetting resin and an energy ray (ultraviolet ray, electron beam) curable resin are preferable because they have a low elastic modulus during vapor deposition and can be cross-linked after vapor deposition to increase the elastic modulus. is there.

  In the binder, silane coupling agent, silane, titanate coupling agent, aluminate so that the plasma atomized or ionized magnetic material or electromagnetic wave absorber 3 partially reacts with the binder and stabilizes. A coupling agent, a nonionic surfactant, a polar resin oligomer, and the like may be blended. By adding such additives, in addition to preventing oxidation of the magnetic material, it prevents the formation of a homogeneous film due to agglomeration of the deposited magnetic material atoms, prevents reflection of conduction noise by the homogeneous film, and absorbs it. The characteristics can be improved.

  A reinforcing filler, a flame retardant, a flame retardant aid, an anti-aging agent, an antioxidant, a colorant, a plasticizer, a lubricant, a heat improver and the like may be appropriately added to the binder 2. In addition, it is also possible to improve the environmental characteristics by depositing a silicon oxide or silicon nitride after the magnetic material is deposited.

(Electromagnetic wave absorber)
Examples of the electromagnetic wave absorbing material 3 in the present invention include particulate or fibrous conductive materials such as carbon and graphite; magnetic particles such as metal-based soft magnetic materials, oxide-based magnetic materials, and nitride-based magnetic materials. . These may be used alone or in combination of two or more. The electromagnetic wave absorbing material 3 has a high electric resistance in a high frequency range of several hundred MHz to several GHz, so that reflection of electromagnetic wave noise due to eddy current is suppressed and has a large magnetic loss, that is, an imaginary part permeability μ ″. In view of this, magnetic particles such as metal-based soft magnetic materials, oxide-based magnetic materials, and nitride-based magnetic materials are preferable.

Examples of the shape of the magnetic particles include a flat shape, a needle shape, and a spherical shape, and flat magnetic particles are preferable because they have a good radiation noise suppressing effect. When flat magnetic particles are used, since the filling amount of the magnetic particles tends to decrease, spherical magnetic particles may be used in combination.
The average particle diameter of the flat magnetic particles is preferably 0.5 to 100 μm, and the aspect ratio is preferably 2 to 80. When the average particle size is less than 0.5 μm, the specific surface area of the particles becomes too large and it may be difficult to achieve high packing. When the average particle diameter exceeds 100 μm, part of the magnetic particles is exposed from the surface of the EMC countermeasure member, and as a result, the conduction noise suppressing effect may be impaired.

  The average particle diameter of the spherical magnetic particles is preferably 0.5 to 100 μm. When the average particle size is less than 0.5 μm, the specific surface area of the particles becomes too large and it may be difficult to achieve high packing. When the average particle diameter exceeds 100 μm, part of the magnetic particles is exposed from the surface of the EMC countermeasure member, and as a result, the conduction noise suppressing effect may be impaired.

  Metallic soft magnetic materials include iron, carbonyl iron, and Fe-Ni, Fe-Co, Fe-Cr, Fe-Si, Fe-Al, Fe-Cr-Si, Fe-Cr-Al, Fe-Al- Specific examples include iron alloys such as Si and Fe—Pt. These metallic soft magnetic materials may be used alone or in combination of two or more. In addition to iron and iron alloys, metals such as cobalt and nickel, or alloys thereof may be used.

Examples of the oxide-based magnetic material include ferrite. Specific examples thereof include MnFe ₂ O ₄ , CoFe ₂ O ₄ , NiFe ₂ O ₄ , CuFe ₂ O ₄ , ZnFe ₂ O ₄ , MgFe ₂ O ₄ , Fe ₃ O ₄ , Cu—Zn-ferrite, Ni—Zn. - ferrite, Mn-Zn- _{ferrite, Ba 2 Co 2 Fe 12 O} 22, Ba 2 Ni 2 Fe 12 O 22, Ba 2 Zn 2 Fe 12 O 22, Ba 2 Mn 2 Fe 12 O 22, Ba 2 Zn 2 Fe Examples thereof include ₁₂ O ₂₂ , Ba ₂ Mn ₂ Fe ₁₂ O ₂₂ , Ba ₂ Mg ₂ Fe ₁₂ O ₂₂ , Ba ₂ Cu ₂ Fe ₁₂ O ₂₂ , Ba ₂ Co ₂ Fe ₂₄ O _{41 and the} like. One type of these ferrites may be used alone, or two or more types may be used in combination.

Specific examples of the nitride-based magnetic material include Fe ₂ N, Fe ₃ N, Fe ₄ N, and Fe ₁₆ N ₂ . These nitride-based soft magnetic materials are suitable because of their high magnetic permeability and excellent corrosion resistance.

The blending amount of the electromagnetic wave absorber 3 varies depending on the types of the binder 2 and the electromagnetic wave absorber 3, but is 50 parts by mass to 2000 parts by mass, preferably 200 parts by mass to 1500 parts by mass with respect to 100 parts by mass of the binder. . When the blending amount of the electromagnetic wave absorbing material 3 is less than 50 parts by mass, the radiation noise suppressing effect of the EMC countermeasure member may not be sufficient. When the blending amount of the electromagnetic wave absorbing material 3 exceeds 2000 parts by mass, it becomes difficult to mold the EMC countermeasure member, and the obtained EMC countermeasure member loses flexibility and becomes hard and brittle.
The electromagnetic wave absorbing material 3 includes a silane coupling agent, a silane, a titanate coupling agent, an aluminate coupling agent, a nonionic surfactant, a polar resin oligomer, etc., in order to stabilize the binder. You may mix | blend to the grade which does not impair the effect of.

(Magnetic material)
The magnetic material in the present invention is preferably a metallic soft magnetic material containing one or more elements selected from the group consisting of iron, cobalt, and nickel. Since these are deposited on the binder by physical vapor deposition, they are usually used as rectangular or circular targets with a purity of 99 to 99.999%. If the magnetic material is an oxide-based magnetic material that exhibits the characteristics of the magnetic material due to crystallinity, the reason for this is not clear, but the crystallinity of the magnetic material is destroyed by integration with the binder. It seems that performance is not exhibited and does not have a sufficient conduction noise suppression function. The metal-based soft magnetic material described above is believed to form a nanometer-level heterostructure formed by integration with a binder, and exhibit a conduction noise suppression effect.

<Method for manufacturing EMC countermeasure member>
Hereinafter, the manufacturing method of the EMC countermeasure member 1 is demonstrated.
The EMC countermeasure member 1 is manufactured by forming an electromagnetic wave absorbing composition containing a binder 2 and an electromagnetic wave absorbing material 3 and forming a radiation noise suppressing layer 5 having a skin layer 4 on the surface of which no electromagnetic wave absorbing material 3 exists. A substrate manufacturing process to be manufactured; and a vapor deposition process in which a magnetic material is physically vapor-deposited on the skin layer 4 of the radiation noise suppression layer 5 to form a conduction noise suppression layer 6 on the surface of the radiation noise suppression layer 5. .

(Substrate manufacturing process)
A general kneading method can be used for the preparation of the electromagnetic wave absorbing composition. For example, a method of adding the electromagnetic wave absorbing material 3 to the binder 2 and mixing and dispersing with a mixing roll, kneader, Banbury mixer, planetary mixer, etc .; if the binder 2 is soluble in the solvent, the bond dissolved in the solvent There is a method of adding the electromagnetic wave absorbing material 3 to the solution of the agent 2 and mixing, dispersing and drying with a propeller stirrer.

  As a method of manufacturing the radiation noise suppression layer 5 having the skin layer 4, calendar molding, extrusion molding, injection molding, press molding, or the like can be used. The skin layer 4 is formed as follows, for example. In a mold having good releasability, the binder 2 to which the electromagnetic wave absorbing material 3 is added is transfer molded, the viscosity of the binder 2 is lowered, and the binder 2 is made fluid so that the binder 2 is molded. It is filled in and cured or solidified. Although the electromagnetic wave absorbing material 3 is also moved by the flow of the binder 2, the skin layer 4 is formed because the binder 2 comes into contact with the mold surface. Then, the radiation noise suppression layer 5 having the skin layer 4 can be obtained by peeling at the interface between the binder 2 and the mold. Here, it is important to mold the electromagnetic wave absorber 3 so as not to be exposed from the surface of the radiation noise suppression layer 5. For example, the radiation noise suppression layer 5 obtained by cutting and slicing the molded radiation noise suppression layer 5 with a jig has the electromagnetic wave absorbing material 3 exposed on the surface of the radiation noise suppression layer 5 or electromagnetic wave absorption. If the material 3 itself is cut and sliced, the conduction noise suppression layer 6 is not formed uniformly.

(Deposition process)
First, a general description of physical vapor deposition (PVD) will be given.
In general, the physical vapor deposition method is a method in which a vaporized material is vaporized by some method in a vacuumed container, and the vaporized vaporized material is deposited on a substrate placed nearby to form a thin film. Depending on the vaporization method, it can be divided into an evaporation system and a sputtering system. Examples of the evaporation system include EB vapor deposition and ion plating. Examples of the sputtering system include high-frequency sputtering, magnetron sputtering, and counter target type magnetron sputtering.

  In EB vapor deposition, since the energy of the evaporated particles is as small as 1 eV, the substrate is less damaged and the film tends to be porous and the film strength tends to be insufficient, but the specific resistance of the film is increased.

  According to the ion plating, the argon gas and the ions of the evaporated particles are accelerated and collide with the substrate. Therefore, the energy is larger than that of EB, the particle energy is about 1 KeV, and a film having strong adhesion can be obtained. The adhesion of micro-sized particles called droplets cannot be avoided, and there is a possibility that the discharge stops.

  Magnetron sputtering has a low utilization efficiency of the target (evaporation material), but a strong plasma is generated under the influence of a magnetic field, so that the growth rate is fast and the particle energy is as high as several tens of eV. In the high frequency sputtering, an insulating target can be used.

  Among magnetron sputtering, opposed target type magnetron sputtering generates plasma between opposing targets, encloses the plasma by a magnetic field, and places the substrate outside between opposing targets, producing the desired thin film without being damaged by plasma. It is a method to do. Therefore, it is possible to produce a dense target composition having the same composition as the target composition without resputtering the thin film on the substrate, with a higher growth rate, and without causing collisional relaxation of the sputtered atoms.

  Among the physical vapor deposition methods described above, in the method for producing an EMC countermeasure member of the present invention, ion plating, magnetron sputtering, and counter target type magnetron sputtering are preferable, and counter target type magnetron sputtering is particularly preferable for the following reasons. is there.

  When the binder 2 is made of an organic polymer, the covalent bond energy in the organic polymer is about 4 eV. Specifically, the bond energy of C—C, C—H, Si—O, and Si—C is These are 3.6 eV, 4.3 eV, 4.6 eV, and 3.3 eV, respectively. On the other hand, in ion plating, magnetron sputtering, and opposed target type magnetron sputtering, since the evaporated particles have high energy, it is considered that some chemical bonds of the resin are broken and collide with each other.

  Therefore, in the present invention, if the elastic modulus of the binder 2 made of an organic polymer is sufficiently small, when the magnetic material is deposited, the organic polymer vibrates and moves. A local mixing action with the organic polymer occurs, and the magnetic atoms enter up to about 3 μm from the surface of the binder 2, interacting with the organic polymer and the like, not a homogeneous magnetic film, but a nano film. It is considered that the conduction noise suppressing layer 6 having a meter level heterostructure is formed.

  It is preferable to physically deposit magnetic substance atoms having a particle energy of 5 eV or more on the binder 2 because a large amount of the magnetic substance can be dispersed in the binder 2 at one time. That is, since the mass of the magnetic material can be obtained by a single vapor deposition, an EMC countermeasure member having a large conduction noise suppression efficiency can be easily obtained. Since the rate of vibration and movement of the binder 2 is slower than the particle velocity, the deposition rate is preferably small so as to match the timing of relaxation of the binder, and should be suppressed to about 60 nm / min depending on the magnetic substance. Is preferred.

As the magnetic material used as the evaporation material (target) in the vapor deposition process, a metal-based soft magnetic material, an oxide-based magnetic material, and a nitride-based magnetic material are mainly used. These may be used alone or in combination of two or more.
As the magnetic body, a magnetic body equivalent to that cited as the electromagnetic wave absorbing material 3 can be used. Ceramics such as oxide-based magnetic materials and nitride-based magnetic materials have excellent crystal anisotropy due to their crystal structures. However, when dispersed in the binder by physical vapor deposition, they are sufficient. Cannot take a crystal structure. In addition, when the binder is made of an organic polymer, heating for recrystallization cannot be performed sufficiently because it does not have a sufficient heat-resistant temperature. Since the movement of the binder becomes active, there are cases where the crystal cannot be properly grown. For this reason, the magnetic material used in the vapor deposition step is preferably a metallic soft magnetic material containing one or more elements of iron, cobalt, and nickel.

Metallic soft magnetic materials include iron, carbonyl iron; Fe—Ni, Fe—Co, Fe—Cr, Fe—Si, Fe—Al, Fe—Cr—Si, Fe—Cr—Al, Fe—Al—Si. , Fe-Pt, and the like; cobalt, nickel, and alloys thereof. It is preferable to use nickel alone because it is resistant to oxidation.
When the magnetic material is vapor-deposited on the binder 2, the magnetic material enters the binder 2 as plasma or ionized magnetic atoms, so the composition of the magnetic material finely dispersed in the binder 2 is as follows. The composition ratio of the magnetic material used as the vapor deposition material is not necessarily the same. Moreover, it may react with a part of the binder 2 to cause a change such that the ferromagnetic material becomes a paramagnetic material or an antiferromagnetic material.

The vapor deposition mass of the magnetic material by one physical vapor deposition operation is preferably 200 nm or less in terms of the thickness of the single magnetic material. If the thickness is larger than this, the binder 2 reaches the ability to include the magnetic substance, and the magnetic substance cannot be dispersed in the binder 2 but is deposited on the surface, and a continuous bulk homogeneous film having conductivity is generated. Therefore, the vapor deposition mass of the magnetic material is preferably 100 nm or less, and more preferably 50 nm or less. On the other hand, from the viewpoint of the conduction noise suppression effect, the vapor deposition film thickness of the magnetic material is preferably 0.5 nm or more.
Here, the vapor deposition mass is obtained by vapor-depositing a magnetic material on a hard substrate such as glass or silicon under the same conditions and measuring the deposited thickness.
Although the thickness of the radiation noise suppression layer 5 used in the vapor deposition process is not particularly limited, it is preferably thin for a compact EMC countermeasure member.

<EMC countermeasure method>
FIG. 6 shows the influence of the loss power ratio at 1 GHz depending on the separation distance between the conduction noise suppression layer 6 and the microstrip circuit for measuring the conduction noise suppression effect. More specifically, a polyethylene terephthalate film is interposed between the conduction noise suppression layer 6 and the microstrip circuit for measuring the conduction noise suppression effect, and separated by S ₁₁ (reflection attenuation amount) and S ₁₁ by the S parameter method. It is the result of measuring S ₂₁ (transmission attenuation). According to this, as the distance between the conduction noise suppression layer 6 and the microstrip circuit for measuring the conduction noise suppression effect increases, the loss power ratio becomes smaller, being slightly over 0.4 at 0.2 mm and 0 at 0.4 mm. .3, 0.8mm and 0.2. From this result, the EMC countermeasure member 1 is arranged so that the distance between the conductor of the wiring circuit and the conduction noise suppression layer 6 approaches 0.8 mm or less, preferably 0.4 mm or less, more preferably 0.2 mm or less. It is preferable to arrange in the vicinity. The conduction noise suppression layer 6 is electromagnetically coupled to the conductor of the wiring circuit, reduces crosstalk between the wiring circuits or characteristic impedance mismatch, suppresses unnecessary radiation, and suppresses generation of radiation noise. Can do. In addition, leaked or distant radiation noise is attenuated by the radiation noise suppression layer 5, and an excellent EMC countermeasure effect is exhibited. Here, “the conduction noise suppression layer 6 is electromagnetically coupled to the conductor of the wiring circuit” is based on the current flowing through the wiring circuit even if the conduction noise suppression layer 6 is insulated from the conductor of the wiring circuit. It means that the magnetic field and the electric field act on and affect the conduction noise suppression layer 6.

  FIG. 7 is a diagram illustrating an example in which the EMC countermeasure member 1 is arranged on the printed circuit board 31 on which the electronic components such as the semiconductor package 32 and the chip component 33 and the wiring circuit 34 are mounted. The EMC countermeasure member 1 is closely attached to the electronic component and the circuit board 34 so that the conduction noise suppression layer 6 is electromagnetically coupled to the conductor of the wiring circuit (not shown) inside the electronic component and the wiring circuit 34 on the printed board 31. Let it be used. In the IC or the like, the wiring circuit on the chip is protected by the package. However, it is necessary to avoid making the package thickness more than necessary so that the conduction noise suppression layer 6 can be close to the wiring circuit.

  When the EMC countermeasure member 1 is disposed on the electromagnetic noise generation source, either the radiation noise suppression layer 5 side or the conduction noise suppression layer 6 side may be directed to the electromagnetic noise generation source. Preferably, when the radiation noise suppression layer 6 side is directed to the electromagnetic noise generation source, the internal noise is reduced due to the synergistic effect of the magnetic substance of the conduction noise suppression layer 6 and the electromagnetic wave absorber 3 while the conductive noise suppression effect remains unchanged. This is preferable because the rate is increased, the radiation noise suppressing function is particularly excellent, and EMC measures can be taken. In this case, the distance between the conduction noise suppression layer 6 and the wiring circuit that is an electromagnetic noise generation source is separated by the thickness of the radiation noise suppression layer 5, but due to the coupling between the radiation noise suppression layer 5 and the conduction noise suppression layer 6. It is considered that the effect of suppressing conduction noise is not changed. The distance between the conductor of the wiring circuit and the conduction noise suppression layer 6 referred to in the present invention does not include the thickness of the radiation noise suppression layer 5.

(Function)
The above-described EMC countermeasure member 1 is not completely clarified theoretically, but the magnetic substance in an atomic state is dispersed in the binder 2 so that the binder 2 and the magnetic substance are integrated. Since the conductive noise suppression layer 6 is formed, even with a small amount of magnetic material, the quantum effect derived from the heterostructure at the nanometer level, the magnetic anisotropy / shape anisotropy inherent to the material, and the external magnetic field It has a high resonance frequency body due to anisotropy and the like. Thereby, excellent magnetic characteristics can be exhibited, and even with a small amount of magnetic material, a conduction noise suppression effect can be exhibited in a high frequency band.

Further, by filling the binder 2 of the radiation noise suppression layer 5 with the electromagnetic wave absorber 3, reflection of electromagnetic waves due to eddy currents can be suppressed, and an excellent radiation noise suppression effect can be exhibited.
Moreover, by electrically coupling the conduction noise suppression layer 6 to the wiring circuit in the electronic component protected by the package or the wiring circuit on the printed board, the conduction noise can be suppressed before radiating, Furthermore, due to the synergistic effect of the physically vapor-deposited magnetic material and the electromagnetic wave absorbing material 3, the internal decoupling rate is increased and the radiation noise suppressing function is improved.

Examples are shown below.
(Evaluation)
Cross-sectional observation:
A transmission electron microscope H9000NAR manufactured by Hitachi, Ltd. was used.
Shear modulus:
The shear modulus was measured using a solid analyzer RSA-II manufactured by Rheometric Scientific as a viscoelastic modulus measuring apparatus in a shear mode under a measurement frequency of 1 Hz.
Conductive noise suppression effect:
S ₁₁ (reflection attenuation amount) and S ₂₁ (transmission attenuation amount) by the S-parameter method were measured using a near-field electromagnetic wave absorption material measuring device manufactured by Keycom Corporation. Moreover, the loss power ratio was evaluated. As a network analyzer, a vector network analyzer 37247C manufactured by Anritsu Co., Ltd. was used, and as a test fixture of a microstrip line having an impedance of 50Ω, TF-3A manufactured by Keycom Co., Ltd. was used.

Radiation noise suppression effect:
As shown in FIG. 8, an electromagnetic wave transmitting micro loop antenna 41 (manufactured by Keycom Corporation, 5 mm diameter micro loop antenna) and an electromagnetic wave receiving micro loop antenna 42 (manufactured by NEC Vacuum Glass, Inc., magnetic field probe CP-2S) Are connected to a spectrum analyzer 43 (trade name: R3132, manufactured by Advantest Co., Ltd.), and the electromagnetic wave transmitting micro loop antenna 41 and the electromagnetic wave receiving micro loop antenna 42 are connected between the antennas so as to sandwich the test sheet 44 of the EMC countermeasure member. The minimum spacing of 2 mm was disposed, and the mutual decoupling rate of the EMC countermeasure members was measured.

  Further, as shown in FIG. 9, the electromagnetic wave transmitting micro-loop antenna 41 and the electromagnetic wave receiving micro-loop antenna 42 are placed on the same side of the surface of the test sheet 43 so that the distance between the antennas is 1 mm. The internal decoupling rate of the EMC countermeasure member was measured with an interval of.

Example 1
1. 100 parts by mass of silicone rubber (vinyl group-containing dimethylpolysiloxane), 300 parts by mass of a flat Fe—Cr soft magnetic metal (average particle size: 20 μm, aspect ratio: 19.6), organohydrogenpolysiloxane 2 parts by weight, 0.2 parts by weight of a platinum group catalyst 2% by weight alcohol solution, and 0.1 parts by weight of an acetylene alcohol-based reaction control agent are added and dispersed and mixed with a mixing roll to obtain an electromagnetic wave absorbing composition. It was. The electromagnetic wave absorbing composition was compression-molded at 120 ° C. for 1 hour, and a 500 μm-thick radiation noise suppression layer having a skin layer with an average thickness of 0.63 μm on the surface (shear elasticity of the skin layer binder at 25 ° C. Rate: 2.3 × 10 ⁵ Pa). On the skin layer of the radiation noise suppression layer, a Ni-based soft magnetic metal having a thickness of 20 nm was physically vapor-deposited by a counter target type magnetron sputtering method to form a conduction noise suppression layer, thereby obtaining an EMC countermeasure member. At this time, the temperature of the radiation noise suppression layer was kept at 25 ° C., and a slight negative voltage was applied so that the evaporated particles had a particle energy of 8 eV, and sputtering was performed.

  A part of the conduction noise suppression layer of the obtained EMC countermeasure member was made into a thin piece with a microtome, an ion beam polisher was applied to the cross section, and the cross section of the conduction noise suppression layer was observed with a high resolution transmission electron microscope. The thickness of the conduction noise suppression layer was 45 nm (0.045 μm).

About the obtained EMC countermeasure member, the conduction noise suppression effect and the radiation noise suppression effect were evaluated. Each measurement was performed on both the radiation noise suppression layer side and the conduction noise suppression layer side. Table 1 shows the evaluation results of the conduction noise suppression effect and the radiation noise suppression effect at 1 GHz.
Further, the measurement results of S ₁₁ (reflection attenuation amount) and S ₂₁ (transmission attenuation amount) of 0.05 to 3.0 GHz are shown in FIG. 10, the loss power ratio of 0.05 to 3.0 GHz is shown in FIG. 11, and 100 kHz. The measurement result of the mutual decoupling rate of ˜2.0 GHz is shown in FIG. 12, and the measurement result of the internal decoupling rate of 100 kHz to 2.0 GHz is shown in FIG.

In FIG. 10, ◯ indicates S ₁₁ (reflection loss) measured from the radiation noise suppression layer side when the incident electromagnetic wave amount is set as a reference (0), and ● indicates S ₂₁ (transmission attenuation) measured from the radiation noise suppression layer side. Amount). ◇ indicates S ₁₁ (reflection attenuation) measured from the conduction noise suppression layer side when the incident electromagnetic wave amount is set as a reference (0), and ◆ indicates S ₂₁ (transmission attenuation) measured from the conduction noise suppression layer side. .
In FIG. 11, ◯ indicates the loss power ratio evaluated from the radiation noise suppression layer side, and ◇ indicates the loss power ratio evaluated from the conduction noise suppression layer side.
In FIG. 12, ◯ indicates the mutual decoupling ratio measured by placing the electromagnetic wave transmission microloop antenna 41 on the radiation noise suppression layer side, and ◇ indicates the electromagnetic wave transmission microloop antenna 41 on the conduction noise suppression layer side. The □ indicates the measured mutual decoupling ratio, and □ indicates the mutual decoupling ratio measured by placing the electromagnetic wave transmitting microloop antenna 41 and the electromagnetic wave receiving microloop antenna 42 with the copper foil sandwiched therebetween.
In FIG. 13, ◯ indicates the internal decoupling ratio measured by placing the electromagnetic wave transmission microloop antenna 41 and the electromagnetic wave reception microloop antenna 42 on the radiation noise suppression layer side, and ◇ indicates the electromagnetic wave transmission on the conduction noise suppression layer side. The internal decoupling ratio measured by arranging the microloop antenna 41 and the electromagnetic wave receiving microloop antenna 42 is indicated by □, and the electromagnetic wave transmitting microloop antenna 41 and the electromagnetic wave receiving microloop antenna 42 are arranged on the same side of the surface of the copper foil. The internal decoupling rate measured by placing is shown.

(Example 2)
To 100 parts by mass of silicone rubber (two-component type), 1000 parts by mass of a spherical Fe-Cr soft magnetic material (average particle size: 20 μm) surface-treated with a silane coupling agent is added and dispersed with a mixing roll To obtain an electromagnetic wave absorbing composition. This electromagnetic wave absorbing composition was molded into a sheet shape by compression molding so as to have a thickness of 300 μm, and then a silicone rubber was vulcanized at 150 ° C. for 1 hour to form a skin layer having an average thickness of 0.67 μm on the surface. A radiation noise suppression layer having a thickness of 290 μm (shear elastic modulus at 25 ° C. of the binder of the skin layer: 1.0 × 10 ⁴ Pa) was obtained. On the skin layer of the radiation noise suppression layer, a conductive noise suppression layer was formed by physically vapor-depositing a 50-nm-thick Fe—Ni-based soft magnetic metal by an opposed target type magnetron sputtering method to obtain an EMC countermeasure member. . At this time, the temperature of the radiation noise suppression layer was kept at 25 ° C., and a slight negative voltage was applied so that the evaporated particles had a particle energy of 8 eV, and sputtering was performed.

  A part of the conduction noise suppression layer of the obtained EMC countermeasure member was made into a thin piece with a microtome, an ion beam polisher was applied to the cross section, and the cross section of the conduction noise suppression layer was observed with a high resolution transmission electron microscope. The thickness of the conductive noise suppression layer was 90 nm (0.090 μm).

About the obtained EMC countermeasure member, the conduction noise suppression effect and the radiation noise suppression effect were evaluated. Each measurement was performed in the same manner as in Example 1. Table 1 shows the evaluation results of the conduction noise suppression effect and the radiation noise suppression effect at 1 GHz.
Further, the measurement results of S ₁₁ (reflection attenuation amount) and S ₂₁ (transmission attenuation amount) of 0.05 to 3.0 GHz are shown in FIG. 14, the loss power ratio of 0.05 to 3.0 GHz is shown in FIG. The measurement result of the mutual decoupling rate of ˜2.0 GHz is shown in FIG. 16, and the measurement result of the internal decoupling rate of 100 kHz to 2.0 GHz is shown in FIG.

In FIG. 14, ◯ indicates S ₁₁ (reflection loss) measured from the radiation noise suppression layer side when the incident electromagnetic wave amount is set as a reference (0), and ● indicates S ₂₁ (transmission attenuation) measured from the radiation noise suppression layer side. Amount). ◇ indicates S ₁₁ (reflection attenuation) measured from the conduction noise suppression layer side when the incident electromagnetic wave amount is set as a reference (0), and ◆ indicates S ₂₁ (transmission attenuation) measured from the conduction noise suppression layer side. .
In FIG. 15, ◯ indicates the loss power ratio evaluated from the radiation noise suppression layer side, and ◇ indicates the loss power ratio evaluated from the conduction noise suppression layer side.
In FIG. 16, ◯ indicates the mutual decoupling ratio measured by arranging the electromagnetic wave transmission microloop antenna 41 on the radiation noise suppression layer side, and ◇ indicates the electromagnetic wave transmission microloop antenna 41 on the conduction noise suppression layer side. The □ indicates the measured mutual decoupling ratio, and □ indicates the mutual decoupling ratio measured by placing the electromagnetic wave transmitting microloop antenna 41 and the electromagnetic wave receiving microloop antenna 42 with the copper foil sandwiched therebetween.
In FIG. 17, ◯ indicates the internal decoupling ratio measured by placing the electromagnetic wave transmission microloop antenna 41 and the electromagnetic wave reception microloop antenna 42 on the radiation noise suppression layer side, and ◇ indicates the electromagnetic wave transmission on the conduction noise suppression layer side. The internal decoupling ratio measured by arranging the microloop antenna 41 and the electromagnetic wave receiving microloop antenna 42 is indicated by □, and the electromagnetic wave transmitting microloop antenna 41 and the electromagnetic wave receiving microloop antenna 42 are arranged on the same side of the surface of the copper foil. The internal decoupling rate measured by placing is shown.

(Example 3)
100 parts by mass of urethane resin and 20 parts by mass of an isocyanate compound as a curing agent, and 1600 parts by mass of a flat Fe-Ni soft magnetic material (average particle size: 15 μm, aspect ratio: surface treatment with a titanate coupling agent) 65) and paste with 700 parts by mass of a solvent (a 1: 1 mixture of cyclohexanone and toluene) applied to the coating support by the bar coating method so that the thickness after drying is 1.1 mm. After the film is formed and sufficiently dried, it is vacuum heated and pressed, cured at 85 ° C. for 24 hours, peeled off from the coating support, and has a skin layer with an average thickness of 0.74 μm on the surface. A radiation noise suppression layer having a thickness of 1.0 mm (shear elastic modulus at 25 ° C. of the skin layer binder: 1.7 × 10 ⁶ Pa) was obtained. On the skin layer of the radiation noise suppression layer, a Ni-based soft magnetic metal having a thickness of 10 nm was physically vapor-deposited by an opposed target type magnetron sputtering method to form a composite layer, thereby obtaining an EMC countermeasure member. At this time, the temperature of the radiation noise suppression layer was kept at 25 ° C., and a slight negative voltage was applied so that the evaporated particles had a particle energy of 8 eV, and sputtering was performed.

  A part of the conduction noise suppression layer of the obtained EMC countermeasure member was made into a thin piece with a microtome, an ion beam polisher was applied to the cross section, and the cross section of the conduction noise suppression layer was observed with a high resolution transmission electron microscope. The thickness of the conductive noise suppression layer was 25 nm (0.025 μm).

About the obtained EMC countermeasure member, the conduction noise suppression effect and the radiation noise suppression effect were evaluated. Each measurement was performed in the same manner as in Example 1. Table 1 shows the evaluation results of the conduction noise suppression effect and the radiation noise suppression effect at 1 GHz.
Further, the measurement results of S ₁₁ (reflection attenuation amount) and S ₂₁ (transmission attenuation amount) of 0.05 to 3.0 GHz are shown in FIG. 18, the loss power ratio of 0.05 to 3.0 GHz is shown in FIG. The measurement result of the mutual decoupling rate of ˜2.0 GHz is shown in FIG. 20, and the measurement result of the internal decoupling rate of 100 kHz to 2.0 GHz is shown in FIG.

In FIG. 18, ◯ indicates S ₁₁ (reflection loss) measured from the radiation noise suppression layer side when the amount of incident electromagnetic waves is set as a reference (0), and ● indicates S ₂₁ (transmission attenuation) measured from the radiation noise suppression layer side. Amount). ◇ indicates S ₁₁ (reflection attenuation) measured from the conduction noise suppression layer side when the incident electromagnetic wave amount is set as a reference (0), and ◆ indicates S ₂₁ (transmission attenuation) measured from the conduction noise suppression layer side. .
In FIG. 19, ◯ indicates the loss power ratio evaluated from the radiation noise suppression layer side, and ◇ indicates the loss power ratio evaluated from the conduction noise suppression layer side.
In FIG. 20, ◯ indicates the mutual decoupling ratio measured by arranging the electromagnetic wave transmission microloop antenna 41 on the radiation noise suppression layer side, and ◇ indicates the electromagnetic wave transmission microloop antenna 41 on the conduction noise suppression layer side. The □ indicates the measured mutual decoupling ratio, and □ indicates the mutual decoupling ratio measured by placing the electromagnetic wave transmitting microloop antenna 41 and the electromagnetic wave receiving microloop antenna 42 with the copper foil sandwiched therebetween.
In FIG. 21, ◯ indicates the internal decoupling ratio measured by placing the electromagnetic wave transmission microloop antenna 41 and the electromagnetic wave reception microloop antenna 42 on the radiation noise suppression layer side, and ◇ indicates the electromagnetic wave transmission on the conduction noise suppression layer side. The internal decoupling ratio measured by arranging the microloop antenna 41 and the electromagnetic wave receiving microloop antenna 42 is indicated by □, and the electromagnetic wave transmitting microloop antenna 41 and the electromagnetic wave receiving microloop antenna 42 are arranged on the same side of the surface of the copper foil. The internal decoupling rate measured by placing is shown.

(Comparative Example 1)
For the radiation noise suppression layer before forming the conduction noise suppression layer in Example 1, the conduction noise suppression effect and the radiation noise suppression effect were measured. Each measurement was performed in the same manner as in Example 1. Table 2 shows the evaluation results of the conduction noise suppression effect and the radiation noise suppression effect at 1 GHz.
Further, the measurement results of S ₁₁ (reflection attenuation amount) and S ₂₁ (transmission attenuation amount) of 0.05 to 3.0 GHz are shown in FIG. 22, the loss power ratio of 0.05 to 3.0 GHz is shown in FIG. 23, and 100 kHz. FIG. 24 shows the measurement result of the mutual decoupling rate of ˜2.0 GHz, and FIG. 25 shows the measurement result of the internal decoupling rate of 100 kHz to 2.0 GHz.

In FIG. 22, ◯ indicates the return loss when the amount of incident electromagnetic waves is the reference (0), and ● indicates the transmission loss.
In FIG. 24, ◯ indicates the mutual decoupling rate of Comparative Example 1, and □ indicates the mutual decoupling rate of the copper foil.
In FIG. 25, ◯ indicates the internal decoupling rate of Comparative Example 1, and □ indicates the internal decoupling rate of the copper foil.

(Comparative Example 2)
100 parts by mass of silicone rubber (vinyl group-containing dimethylpolysiloxane), 1.2 parts by mass of organohydrogenpolysiloxane, 0.2 parts by mass of a 2% alcohol solution of a platinum group catalyst, 0.1% of acetylene alcohol-based reaction control agent A part by mass was added and dispersed and mixed with a mixing roll to obtain a silicone composition. This silicone composition was made into a toluene solution (concentration: 20% by mass) and coated on a polyethylene terephthalate film (thickness: 50 μm) so that the thickness of the silicone rubber after heat drying and vulcanization was 20 μm. It was heated at 120 ° C. for 1 hour and cured to obtain a silicone rubber-polyethylene terephthalate multilayer film (shear elastic modulus at 25 ° C. of the skin layer: 20 × 10 ⁵ Pa). A conductive noise suppression layer is formed by physically vapor-depositing Ni-based soft magnetic metal having a thickness of 20 nm on the obtained multilayer film silicone rubber by a counter-target magnetron sputtering method, and an EMC countermeasure member is formed. Obtained. At this time, the temperature of the silicone rubber was kept at 25 ° C., and a slight negative voltage was applied so as to have an energy of 8 eV, and sputtering was performed.

  A part of the conduction noise suppression layer of the obtained EMC countermeasure member was made into a thin piece with a microtome, an ion beam polisher was applied to the cross section, and the cross section of the conduction noise suppression layer was observed with a high resolution transmission electron microscope. The thickness of the conductive noise suppression layer was 50 nm (0.050 μm).

About the obtained EMC countermeasure member, the conduction noise suppression effect and the radiation noise suppression effect were evaluated. Each measurement was performed in the same manner as in Example 1. Table 2 shows the evaluation results of the conduction noise suppression effect and the radiation noise suppression effect at 1 GHz.
Further, S ₁₁ (return loss) of 0.05~3.0GHz and S ₂₁ the measurement results of (transmission attenuation) in FIG. 26, the loss power ratio transmission noise suppressing layer side 0.05~3.0GHz 27 shows the measurement results of the mutual decoupling rate from 100 kHz to 2.0 GHz. FIG. 28 shows the measurement results of the 100 kHz to 2.0 GHz internal decoupling rate.

In FIG. 26, ◯ indicates S ₁₁ (reflection loss) measured from the conduction noise suppression layer side when the incident electromagnetic wave amount is set as a reference (0), and ● indicates S ₂₁ (transmission attenuation) measured from the conduction noise suppression layer side. Amount).
In FIG. 28, ◯ indicates the mutual decoupling rate measured by placing the electromagnetic wave transmission microloop antenna 41 on the conductive noise suppression layer side of Comparative Example 2, and □ indicates the electromagnetic wave transmission microloop antenna 41 with the copper foil sandwiched therebetween. And the mutual decoupling rate measured by arranging the electromagnetic wave receiving microloop antenna 42 is shown.
In FIG. 29, ◯ indicates the internal decoupling ratio measured by placing the electromagnetic wave transmission micro loop antenna 41 and the electromagnetic wave reception micro loop antenna 42 on the conductive noise suppression layer side of Comparative Example 2, and □ indicates the electromagnetic wave transmission micro loop. The internal decoupling rate measured by arranging the loop antenna 41 and the electromagnetic wave receiving micro loop antenna 42 on the same side of the surface of the copper foil is shown.

(Comparative Example 3)
The copper foil (thickness: 15 μm) was evaluated for radiation noise suppression effect. Each measurement was performed in the same manner as in Example 1. Table 2 shows the evaluation results of the radiation noise suppression effect at 1 GHz.

  As shown in Tables 1-2 and FIGS. 10-29, the EMC countermeasure members obtained in Examples 1 to 3 each have a loss power ratio of 0.3 or more when the frequency is 1 GHz, and the mutual decoupling rate is It was −1 dB or more, the internal decoupling rate was −1 dB or more, and it was confirmed that the conduction noise suppression effect and the radiation noise suppression effect were excellent. Also, when the internal decoupling rate is measured from the radiation noise suppression layer side, the internal decoupling rate is compared with the magnetic material of the conduction noise suppression layer compared to the case where the internal decoupling rate is measured from the conduction noise suppression layer side. Due to the synergistic effect with the electromagnetic wave absorbing material, the radiation noise suppression layer side was 10% or more superior to the conduction noise suppression layer side.

On the other hand, in Comparative Example 1, since the electromagnetic wave absorbing material was simply dispersed and mixed in the binder, both the mutual decoupling rate and the internal decoupling rate at 1 GHz were −1 dB or more. Was 0.1 or less, and the effect of suppressing conduction noise was low.
In Comparative Example 2, a Ni-based soft magnetic metal was deposited on the binder by a counter target magnetron sputtering method to form a conduction noise suppression layer, and the loss power ratio at 1 GHz was 0.3 or more. Yes, it had a good conduction noise suppression effect, but the mutual decoupling rate was -1 dB or less, and the internal decoupling rate was on the plus side like the copper foil, and secondary radiation noise was generated.

  The EMC countermeasure member of the present invention is a thin and lightweight EMC countermeasure member having two excellent electromagnetic noise suppression functions, namely, a conduction noise suppression function and a radiation noise suppression function. It becomes possible to cope with weight reduction and multi-function.

It is a schematic sectional drawing which shows an example of the EMC countermeasure member of this invention. It is a schematic sectional drawing which shows the other example of the EMC countermeasure member of this invention. It is a schematic sectional drawing which shows the other example of the EMC countermeasure member of this invention. It is a high-resolution transmission electron microscope image of the conduction noise suppression layer in the EMC countermeasure member of the present invention. It is a schematic diagram which shows an example of the vicinity of a conduction noise suppression layer. It is a graph which shows the relationship between the separation distance of the conduction noise suppression layer and the microstrip circuit which measures the conduction noise suppression effect, and the loss power ratio in 1 GHz. It is sectional drawing which shows an example of the printed circuit board carrying the EMC countermeasure member and electronic component of this invention. It is the schematic which shows the measuring apparatus of a mutual decoupling rate. It is the schematic which shows the measuring apparatus of an internal decoupling rate. EMC countermeasure member S ₁₁ of Example 1 is a graph showing the (return loss) and S ₂₁ (transmission attenuation). 6 is a graph showing a loss power ratio of an EMC countermeasure member of Example 1. It is a graph which shows the mutual decoupling rate of the EMC countermeasure member of Example 1, and copper foil. It is a graph which shows the EMC countermeasure member of Example 1, and the internal decoupling rate of copper foil. EMC countermeasure member S ₁₁ of Example 2 is a graph showing the (return loss) and S ₂₁ (transmission attenuation). It is a graph which shows the loss power ratio of the EMC countermeasure member of Example 2. It is a graph which shows the mutual decoupling rate of the EMC countermeasure member of Example 2, and copper foil. It is a graph which shows the EMC countermeasure member of Example 2, and the internal decoupling rate of copper foil. EMC countermeasure member S ₁₁ of Example 3 is a graph showing the (return loss) and S ₂₁ (transmission attenuation). 6 is a graph showing a loss power ratio of an EMC countermeasure member of Example 3. It is a graph which shows the mutual decoupling rate of the EMC countermeasure member of Example 3, and copper foil. It is a graph which shows the EMC countermeasure member of Example 3, and the internal decoupling rate of copper foil. Radiation noise suppressing layer of S ₁₁ of Comparative Example 1 is a graph showing the (return loss) and S ₂₁ (transmission attenuation). 5 is a graph showing a loss power ratio of a radiation noise suppression layer of Comparative Example 1. It is a graph which shows the mutual decoupling rate of the radiation noise suppression layer of comparative example 1, and copper foil. It is a graph which shows the radiation noise suppression layer of the comparative example 1, and the internal decoupling rate of copper foil. EMC countermeasure member S ₁₁ of Comparative Example 2 is a graph showing the (return loss) and S ₂₁ (transmission attenuation). 6 is a graph showing a loss power ratio of an EMC countermeasure member of Comparative Example 2. It is a graph which shows the mutual decoupling rate of the EMC countermeasure member of Comparative Example 2, and copper foil. It is a graph which shows the EMC countermeasure member of the comparative example 2, and the internal decoupling rate of copper foil.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 EMC countermeasure member 2 Binder 3 Electromagnetic wave absorber 4 Skin layer 5 Radiation noise suppression layer 6 Conduction noise suppression layer 10 EMC countermeasure member 20 EMC countermeasure member

Claims (5)

By physical vapor deposition, shear modulus during physical vapor deposition is a binding agent is ^{1 × 10 3 ~1 × 10 7} Pa, by depositing a magnetic material was dispersed the magnetic material in the sintered material mixture A conduction noise suppression layer;
Binder and containing an electromagnetic absorbing material possess a radiation noise suppressing layer, the thickness of the conductive noise suppressing layer, EMC countermeasure member, wherein 0.005~0.3μm der Rukoto.   2. The EMC countermeasure member according to claim 1, wherein the magnetic body is a metallic soft magnetic body containing one or more elements selected from the group consisting of iron, cobalt, and nickel. Wherein the binder is, EMC countermeasure member according to claim 1 or 2, characterized in that an organic polymer. The EMC countermeasure member according to any one of claims 1 to 3 is disposed near a wiring circuit in an electronic component or a wiring circuit on a printed circuit board, and a conductive noise suppression layer is a conductor or printed circuit of the wiring circuit in the electronic component. An EMC countermeasure method, characterized by being arranged so as to be electromagnetically coupled to a conductor of a wiring circuit on a substrate. 5. The EMC countermeasure method according to claim 4 , wherein a distance between the conductor of the wiring circuit in the electronic component or the conductor of the wiring circuit on the substrate and the conduction noise suppression layer is 0.8 mm or less.

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