JP2006093414A - Conduction noise suppressor and conduction noise countermeasure method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a conduction noise suppressor having a conduction noise suppressing function, and also to provide a conduction noise countermeasuring method using the same. <P>SOLUTION: The conduction noise suppressor 1 comprises: a base substance 2 containing a binder; and a conduction noise suppressing layer 3 which is the integral body of part of the binder of the base substance 2 and a metallic soft magnetic substance containing one ore more elements selected among a group of iron, cobalt, and nickel. The conduction noise suppressor 1 is arranged near a wiring circuit inside an electronic component or near a wiring circuit on a substrate so that the conduction noise suppressing layer 3 is electromagnetically coupled to a conductor of the wiring circuit inside the electronic component or with a conductor of the wiring circuit on the substrate. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a conduction noise suppressor and a conduction noise 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.
“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

  Therefore, the objective of this invention is providing the conduction noise suppression body provided with the conduction noise suppression function, and the conduction noise countermeasure method using the same.

  That is, the conductive noise suppressor of the present invention comprises a base containing a binder; a part of the base binder, and a metal-based soft containing one or more elements selected from the group consisting of iron, cobalt, and nickel. It has a conductive noise suppression layer formed integrally with a magnetic body.

Here, the conductive noise suppression layer is a layer in which a metallic soft 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. It is desirable that
The conductive noise suppression layer preferably has a thickness of 0.005 to 0.3 μm.
The binder is preferably an organic polymer.

The conductive noise suppression method of the present invention includes the conductive noise suppression body of the present invention near the wiring circuit in the electronic component or the wiring circuit on the substrate, and the conductive noise suppression layer is a conductor of the wiring circuit in the electronic component or It arrange | positions so that it may couple | bond with the conductor of the wiring circuit on a board | substrate 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.

  The conductive noise suppressor of the present invention is a conductive noise formed by integrating a part of the binder of the base and a metal-based soft magnetic material containing one or more elements selected from the group consisting of iron, cobalt and nickel. Since it has a suppression layer, it has a conduction noise suppression function. In addition, a metal-based soft magnetic material containing one or more elements selected from the group consisting of iron, cobalt, and nickel includes oxide-based magnetic materials, nitride-based magnetic materials that exhibit magnetic properties due to crystal anisotropy, and On the other hand, since heating for recrystallization is not necessary, the manufacturing process of the conductive noise suppressor is not troublesome, and a lightweight organic polymer having flexibility can be used as a binder.

The conductive noise suppression layer is a layer in which a metallic soft magnetic material is dispersed in a binder having a shear modulus of 1 × 10 ³ to 1 × 10 ⁷ Pa by physical vapor deposition. If present, the conduction noise suppression effect is further improved.
And if the said binder is an organic polymer, it will be flexible, can be set as a strong conductive noise suppression body, and is excellent in the adhesiveness and followable | trackability to an electronic component etc.
Furthermore, if the thickness of the conductive noise suppression layer is 0.005 to 0.3 μm, the conductive noise suppression effect can be further improved, and a reduction in thickness and weight can be achieved.

The conductive noise suppression method of the present invention includes the conductive noise suppression body of the present invention near the wiring circuit in the electronic component or the wiring circuit on the substrate, and the conductive noise suppression layer is a conductor of the wiring circuit in the electronic component or Since it is a method of being arranged so as to be electromagnetically coupled to the conductor of the wiring circuit on the board, it is possible to suppress radiation noise especially from a distance as an EMS countermeasure, and it has been generated from electronic parts as an EMI countermeasure The conduction noise can be suppressed before the conduction 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.
<Conduction noise suppressor>
The conductive noise suppressor of the present invention comprises a base containing a binder; a part of the binder of the base; and a metal-based soft magnetic body containing one or more elements selected from the group consisting of iron, cobalt and nickel And a conductive noise suppression layer formed integrally with each other.

As such a conduction noise suppression body, for example, as shown in FIG. 1, a base 2 containing a binder; a part of the binder of the base 2 and a metal-based soft magnetic body are integrated. The conduction noise suppression body 1 which has the suppression layer 3 is mentioned. In addition, as shown in FIG. 2, a conduction noise suppression body 10 in which a base 2 containing a binder is further laminated on the surface of the conduction noise suppression layer 3; two conduction noise suppression bodies as shown in FIG. 1 may be a conduction noise suppression body 20 in which 1 is laminated.
Furthermore, the adhesion function for arrange | positioning the conduction noise suppression body in the electronic device or near the wiring circuit on a board | substrate may be provided to the surface of the conduction noise suppression body.

The conduction noise suppression body 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, and 0.4 to 0.95. It is more preferable that
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 make the loss power ratio of the conduction noise suppressor 0.3 to 0.95, in the production of the conduction noise suppressor, by performing physical vapor deposition at high energy, It can be achieved by integrating the metal-based soft magnetic material atoms as a basis and selecting the physical vapor deposition conditions and the metal-based soft magnetic material deposition amount as appropriate.

In the conduction noise suppressing body of the present invention, the mutual decoupling rate at 1 GHz, which is an index of the radiation noise suppressing effect, is preferably −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 a conduction noise suppressor. The internal decoupling rate is the amount by which the coupling between transmission lines or the same printed circuit board is attenuated by installing a conduction noise suppressor (Shigeru Takeda, “Current Status of IEC Standardization of Noise Suppression Sheets” "The 131st meeting of the study group, Japan Society of Applied Magnetics, July 4, 2003, p.33-36).

(Conduction noise suppression layer)
The conductive noise suppression layer is a layer in which a metallic soft magnetic material is dispersed in a binder having a shear modulus of 1 × 10 ³ to 1 × 10 ⁷ Pa during physical vapor deposition, for example, by physical vapor deposition. Preferably there is.
The conductive noise suppression layer 3 formed in this way is formed of a metal-based soft magnetic material on the surface of the substrate 2 as shown in FIG. 5 which is a schematic diagram of the high-resolution transmission electron microscope image of FIG. Is a layer obtained by physically vapor-depositing a metal-based soft magnetic material that is dispersed and integrated in a binder in an atomic state without forming a homogeneous film.

  The conduction noise suppression layer 3 has a crystal lattice 11 in which metal-based soft magnetic atoms arranged at intervals of several angstroms are observed as a very small crystal, and a portion that is recognized as being in a flake state and a very small range. It consists of a portion where only the binder 4 in which no metallic soft magnetic material is present is observed, and a portion where the metallic soft magnetic material atoms 13 are dispersed and observed in the binder 4 without being crystallized. In other words, no grain boundary indicating that the metal-based soft magnetic material is present as fine particles having a clear crystal structure was observed, and a complex heterostructure (non-homogeneous / non-uniform) in which the metal-based soft magnetic material and the binder were integrated at the nanometer level. Asymmetric structure).

  The thickness of the conduction noise suppression layer 3 is the depth at which the metallic soft magnetic atoms have penetrated the surface of the substrate 2 and depends on the deposition mass of the metallic soft magnetic material, the binder material, the physical vapor deposition conditions, and the like. However, it becomes about 1.5 to 3.0 times the vapor deposition thickness of the metallic soft magnetic material. Here, the vapor deposition thickness of the metal-based soft magnetic material means a film thickness when the metal-based soft magnetic material is physically vapor-deposited on a hard base material in which metal-based soft magnetic material atoms do not enter.

  By setting the thickness of the conductive noise suppression layer 3 to 0.005 μm or more, the metal soft magnetic atoms can be dispersed and integrated with the binder 4 and a large magnetic loss in the high frequency region due to shape anisotropy can be obtained. It is considered to have characteristics, and a sufficient conduction noise suppression effect can be exhibited. On the other hand, when the thickness of the conduction noise suppression layer 3 exceeds 0.3 μm, a homogeneous metal soft magnetic film is formed through a clear crystal structure, returning to the bulk metal soft magnetic material, and having a different shape. The directivity is reduced and the conduction noise suppression effect is reduced, which 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 3 is several times to several hundred times larger than the value calculated from the specific resistance of the bulk metallic soft magnetic material, but the surface resistance is about 10 ¹ to 10 ³ Ω / cm ^2. Therefore, when the conductive noise suppression layer 3 is disposed in the vicinity of the conductor, it is important to take sufficient insulation measures.

(Binder)
The binder 4 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 4, a material having a low shear elastic modulus is used in the physical vapor deposition of the metal soft magnetic material to be described later in terms of ease of entering the metal soft magnetic material into the binder 4. . Specifically, the shear modulus of the binder 4 at the time of physical vapor deposition of the metallic soft 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 4 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 4 is preferably 1 × 10 ³ to 1 × 10 ⁶ Pa.

The following methods are known as methods for measuring the shear modulus.
(1) A tensile elastic modulus is obtained from the relationship between tensile stress and strain defined in JIS K7113, and a 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 by setting the test mode to the shear mode.
(3) Using a viscoelasticity measuring device, the storage elastic modulus G ′ and the loss elastic modulus G ″ are measured in the test mode tensile mode, 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 4, 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 4 is used, the base body 2 itself exhibits adhesiveness. Therefore, when the conductive noise suppression body is disposed on an LSI, a peripheral semiconductor, or a flexible wiring board, an adhesive layer and an adhesive layer are not provided. Even if it can arrange | position. However, when a gel-like, paste-like or oil-like component is added, these components may bleed from the substrate 2. 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 4 is preferably one having a high shear modulus after physical vapor deposition of the metal-based soft 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 4 after physical vapor deposition of the metallic soft magnetic material, it is ensured that the nanometer level metallic soft magnetic material atoms or clusters aggregate and crystallize and grow into fine particles. Can be prevented. Specifically, the thing of 1 * 10 < ⁷ > Pa or more is preferable in the temperature range where a conduction noise suppression body is used. In order to obtain a desired shear modulus, it is preferable to crosslink the binder after physical vapor deposition of the metallic soft 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.

  Silane coupling agent, silane, titanate coupling agent, aluminate coupling in the binder so that the plasma soft or ionized metal-based soft magnetic atoms partially react with the binder and stabilize. An agent, a nonionic surfactant, a polar resin oligomer, and the like may be blended. By blending such additives, in addition to preventing oxidation of the metallic soft magnetic material, it prevents the formation of a homogeneous film due to agglomeration of the deposited metallic soft magnetic material atoms, thereby reducing conduction noise caused by the homogeneous film. It can prevent reflection and improve the absorption characteristics.

  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 4. In addition, after vapor deposition of the metal-based soft magnetic material, it is also possible to further deposit silicon oxide or silicon nitride to improve the environmental characteristics.

(Electromagnetic wave absorber)
The substrate 2 may contain an electromagnetic wave absorber. Since the base | substrate 2 containing an electromagnetic wave absorber functions as a radiation noise suppression layer, the conduction noise suppression body obtained becomes an EMC countermeasure member which has both a conduction noise suppression function and a radiation noise suppression function.
Examples of the electromagnetic wave absorbing material 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 has a high electric resistance in a high frequency range of several hundreds of MHz to several GHz, so that reflection of electromagnetic wave noise due to eddy current is suppressed, and it has a large magnetic loss, that is, an imaginary part permeability μ ”. Thus, 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 conduction noise suppressing body, 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 conduction noise suppressing body, 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.

Although the compounding quantity of an electromagnetic wave absorber changes with kinds of binder and electromagnetic wave absorber, it is 50 mass parts-2000 mass parts with respect to 100 mass parts of binders, Preferably it is 200 mass parts-1500 mass parts. When the blending amount of the electromagnetic wave absorbing material is less than 50 parts by mass, the radiation noise suppressing effect of the conduction noise suppressing body may not be sufficient. When the blending amount of the electromagnetic wave absorbing material exceeds 2000 parts by mass, it becomes difficult to form the conduction noise suppression body, and the obtained conduction noise suppression body loses flexibility and becomes hard and brittle.
In order to stabilize the electromagnetic wave absorber with the binder, a silane coupling agent, a silane, a titanate coupling agent, an aluminate coupling agent, a nonionic surfactant, a polar resin oligomer, etc. You may mix | blend to such an extent that an effect is not impaired.

(Metal-based soft magnetic material)
The metallic soft magnetic material used for the conduction noise suppressing layer 3 contains 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 producing conductive noise suppressor>
Hereinafter, the manufacturing method of the conduction noise suppression body 1 is demonstrated about the case where the base | substrate 2 contains an electromagnetic wave absorber.
The method for manufacturing the conduction noise suppressing body 1 includes a base body manufacturing process in which an electromagnetic wave absorbing composition containing a binder and an electromagnetic wave absorbing material is formed to manufacture a base body 2 having a skin layer on the surface of which no electromagnetic wave absorbing material exists. A vapor deposition step in which a metal-based soft magnetic material is physically vapor-deposited on the skin layer of the substrate 2 to form a conductive noise suppression layer 3 on the surface of the substrate 2.

(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 an electromagnetic wave absorbing material to a binder and mixing and dispersing with a mixing roll, kneader, Banbury mixer, planetary mixer, etc .; if the binder is soluble in the solvent, in the binder solution dissolved in the solvent There is a method of adding an electromagnetic wave absorbing material to the mixture, mixing and dispersing with a propeller stirrer, and drying.

  As a method for producing the substrate 2 having a skin layer, calendar molding, extrusion molding, injection molding, press molding, or the like can be used. The skin layer is formed, for example, as follows. In a mold having good releasability, transfer molding of a binder to which an electromagnetic wave absorber is added, lowering the viscosity of the binder, making the binder fluid, filling the mold with the binder, Cure or solidify. The electromagnetic wave absorbing material also moves due to the flow of the binder, but since the binder comes into contact with the mold surface, a skin layer is formed. Then, the base | substrate 2 which has a skin layer can be obtained by peeling in the interface of a binder and a type | mold. Here, it is important to mold the electromagnetic wave absorbing material so as not to be exposed from the surface of the substrate 2. For example, in the base 2 obtained by cutting and slicing the molded base 2 with a jig, the electromagnetic wave absorbing material is exposed on the surface of the base 2 or the electromagnetic wave absorbing material itself is cut and sliced. The conduction noise suppression layer 3 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 is characterized by a high growth rate and high particle energy of several tens of eV because the plasma (strong evaporation) is generated under the influence of a magnetic field although the utilization efficiency of the target (evaporation material) is low. 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.

  In the present invention, these physical vapor deposition methods are used to disperse the magnetic material in the substrate 2 in an atomic state without forming a thin film of the magnetic material on the substrate 2. Therefore, among the above physical vapor deposition methods, in the method for producing a conduction noise suppressor of the present invention, ion plating, magnetron sputtering, and counter target type magnetron sputtering are preferred for the following reasons, particularly counter target type magnetron sputtering. Is preferred.

  When the binder is made of an organic polymer, the covalent bond energy in the organic polymer is about 4 eV. Specifically, the bond energies of C—C, C—H, Si—O, and Si—C are respectively 3.6 eV, 4.3 eV, 4.6 eV, and 3.3 eV. 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, when the elastic modulus of the binder composed of the organic polymer is sufficiently small, the organic polymer vibrates and moves when the metal-based soft magnetic material is vapor-deposited. A local mixing action of soft magnetic atoms and organic polymer occurs, and metal-based soft magnetic atoms enter from the surface of the binder to a maximum of about 3 μm, causing interaction with organic polymers and the like. It is considered that the conduction noise suppression layer 3 having a nanometer level heterostructure is formed instead of the metal-based soft magnetic film.

  It is preferable to physically deposit metal-based soft magnetic atoms having a particle energy of 5 eV or more on the binder because a large amount of the metal-based soft magnetic material can be dispersed in the binder at one time. That is, since the mass of the metal-based soft magnetic material can be gained by a single vapor deposition, a conductive noise suppression body having a large conductive noise suppression efficiency can be easily obtained. The deposition rate is preferably small so as to match the timing of relaxation of the binder, since the speed of vibration and movement of the binder is slower than the particle speed, and varies depending on the metal-based soft magnetic material, but is approximately 60 nm / min. It is preferable to suppress.

  Metallic soft magnetic materials used as evaporation materials (targets) in the vapor deposition step, and metal soft magnetic materials equivalent to those listed as electromagnetic wave absorbing materials 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, in the vapor deposition step, a metallic soft magnetic material containing one or more elements of iron, cobalt, and nickel is used.

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 metal soft magnetic material is vapor-deposited on the binder, the metal soft magnetic material enters the binder as plasma or ionized metal soft magnetic atoms, so that it is finely dispersed in the binder. The composition of the metallic soft magnetic material is not necessarily the same as the composition ratio of the metallic soft magnetic material used as the vapor deposition material. Moreover, it may react with a part of the binder to cause a change such as a paramagnetic substance or an antiferromagnetic substance.

The vapor deposition mass of the metal-based soft magnetic material by one physical vapor deposition operation is preferably 200 nm or less in terms of the thickness of the single metal-based soft magnetic material. If it is thicker than this, the binder will have the ability to include the metal-based soft magnetic material, and the metal-based soft magnetic material will not disperse in the binder and will deposit on the surface, producing a continuous bulk homogeneous film with conductivity. Resulting in. Therefore, the deposition mass of the metallic soft 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 metal-based soft magnetic material is preferably 0.5 nm or more.
Here, the vapor deposition mass is obtained by vapor-depositing a metal soft magnetic material on a hard substrate such as glass or silicon under the same conditions and measuring the deposited thickness.
The thickness of the substrate 2 used in the vapor deposition process is not particularly limited, but it is preferably thin for a compact conductive noise suppressor.

<Measures against conduction noise>
FIG. 6 shows the influence of the loss power ratio at 1 GHz depending on the separation distance between the conduction noise suppression layer 3 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 3 and the microstrip circuit for measuring the conduction noise suppression effect, and separated by S ₁₁ (reflection attenuation amount) and S 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 3 and the microstrip circuit for measuring the conduction noise suppression effect increases, the loss power ratio decreases, and is slightly over 0.4 at 0.2 mm and 0 at 0.4 mm. .3, 0.8mm and 0.2. From this result, the conductive noise suppression body 1 is wired so that the distance between the conductor of the wiring circuit and the conductive noise suppression layer 3 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 of the circuit. The conduction noise suppression layer 3 is electromagnetically coupled to the conductors 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 substrate 2 containing the electromagnetic wave absorbing material, and an excellent EMC countermeasure effect is exhibited. Here, “the conduction noise suppression layer 3 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 3 is insulated from the conductor of the wiring circuit. It means that the magnetic field and electric field act on and affect the conduction noise suppression layer 3.

  FIG. 7 is a diagram illustrating an example in which the conduction noise suppression body 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 conductive noise suppression body 1 is placed on the electronic component and the circuit board 34 so that the conductive noise suppression layer 3 is electromagnetically coupled to the conductor of the wiring circuit (not shown) inside the electronic component and the wiring circuit 34 on the printed circuit board 31. Use in close contact. In the IC or the like, the wiring circuit on the chip is protected by the package, but it is necessary to avoid making the thickness of the package more than necessary so that the conductive noise suppression layer 3 can be close to the vicinity of the wiring circuit.

  When the conduction noise suppression body 1 is disposed on the electromagnetic noise generation source, either the base 2 side or the conduction noise suppression layer 3 side may be directed to the electromagnetic noise generation source. Preferably, when the base 2 side is directed to the electromagnetic noise generation source, the conductive noise suppression effect remains unchanged, and the synergistic effect of the metallic soft magnetic material of the conductive noise suppression layer 3 and the electromagnetic wave absorbing material in the base 2 The internal decoupling rate is increased, the radiation noise suppressing function is particularly excellent, and EMC countermeasures can be taken. In this case, the distance between the conduction noise suppression layer 3 and the wiring circuit that is the electromagnetic wave noise generation source is separated by the thickness of the substrate 2, but is substantially separated by the coupling between the substrate 2 and the conduction noise suppression layer 3. That is not to say, and the conduction noise suppression effect seems not to change. The distance between the conductor of the wiring circuit and the conduction noise suppressing layer 3 in the present invention does not include the thickness of the base 2.

(Function)
In the conductive noise suppression body 1 described above, although theoretically not completely clarified, a metallic soft magnetic material in an atomic state is dispersed in the binder 4 so that the binder 4 and the metallic soft body are dispersed. Conductive noise suppression layer 3 integrated with a magnetic material is formed, so that even with a small amount of metal-based soft magnetic material, quantum effects derived from its nanometer-level heterostructure, material-specific magnetic anisotropy It has a high resonance frequency body due to the effects of property / shape anisotropy and anisotropy by an external magnetic field. Thereby, excellent magnetic characteristics can be exhibited, and even with a small amount of metal-based soft magnetic material, a conduction noise suppression effect can be exhibited in a high frequency band.

Further, by filling the binder 4 of the substrate 2 with an electromagnetic wave absorbing material, reflection of electromagnetic waves due to eddy currents can be suppressed, and an excellent radiation noise suppressing effect can be exhibited.
Moreover, by electrically coupling the conduction noise suppression layer 3 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 metal-based soft magnetic material and the electromagnetic wave absorbing material, 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 noise transmitting microloop antenna 41 and the electromagnetic wave receiving microloop antenna 42 are arranged to sandwich the test sheet 44 of the conduction noise suppressor. It arrange | positioned so that the minimum space | interval may become 2 mm, and the mutual decoupling rate of the conduction noise suppression body 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 conduction noise suppression body was measured with a gap 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 heat compression molded at 120 ° C. for 1 hour, and a 500 μm-thick substrate having a skin layer with an average thickness of 0.63 μm on the surface (shear elastic modulus at 25 ° C. of the binder of the skin layer: 2 .3 × 10 ⁵ Pa) was obtained. A conductive noise suppression body was obtained by physically depositing a Ni-based soft magnetic metal having a thickness of 20 nm on the skin layer of the substrate by an opposed target magnetron sputtering method to form a conductive noise suppression layer. At this time, the substrate temperature 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 portion of the conduction noise suppression layer of the obtained conduction noise suppression body was thinned with a microtome, and 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 conduction noise suppression body, the conduction noise suppression effect and the radiation noise suppression effect were evaluated. Each measurement was performed on both the substrate 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 attenuation) measured from the substrate side when the incident electromagnetic wave amount is set as a reference (0), and ● indicates S ₂₁ (transmission attenuation) measured from the substrate side. ◇ 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 substrate side, and ◇ indicates the loss power ratio evaluated from the conduction noise suppression layer side.
In FIG. 12, ◯ indicates the mutual decoupling rate measured by arranging the electromagnetic wave transmission microloop antenna 41 on the substrate side, and ◇ indicates the mutual measurement measured by arranging the electromagnetic wave transmission microloop antenna 41 on the conduction noise suppression layer side. The symbol □ indicates the mutual decoupling rate measured by placing the electromagnetic wave transmitting micro loop antenna 41 and the electromagnetic wave receiving micro loop 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 base side, and ◇ indicates the electromagnetic wave transmission microloop antenna on the conduction noise suppression layer side. 41 and the electromagnetic decoupling micro-loop antenna 42 measured by placing the electromagnetic wave receiving micro-loop antenna 42, □ represents the electromagnetic wave transmitting micro-loop antenna 41 and the electromagnetic wave receiving micro-loop antenna 42 arranged on the same side of the copper foil surface. The measured internal decoupling rate 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 290 μm-thick substrate (shear elastic modulus at 25 ° C. of the skin layer binder: 1.0 × 10 ⁴ Pa) was obtained. A conductive noise suppression layer was obtained by physically depositing a 50-nm-thick Fe—Ni-based soft magnetic metal on the skin layer of this substrate by facing target type magnetron sputtering to form a conductive noise suppression layer. At this time, the substrate temperature 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 portion of the conduction noise suppression layer of the obtained conduction noise suppression body was thinned with a microtome, and 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 conduction noise suppression body, 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 attenuation) measured from the substrate side when the incident electromagnetic wave amount is set as a reference (0), and ● indicates S ₂₁ (transmission attenuation) measured from the substrate side. ◇ 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 substrate side, and ◇ indicates the loss power ratio evaluated from the conduction noise suppression layer side.
In FIG. 16, ◯ indicates the mutual decoupling rate measured by arranging the electromagnetic wave transmission microloop antenna 41 on the substrate side, and ◇ indicates the mutual measurement measured by arranging the electromagnetic wave transmission microloop antenna 41 on the conduction noise suppression layer side. The symbol □ indicates the mutual decoupling rate measured by placing the electromagnetic wave transmitting micro loop antenna 41 and the electromagnetic wave receiving micro loop antenna 42 with the copper foil sandwiched therebetween.
In FIG. 17, ◯ indicates the internal decoupling ratio measured by arranging the electromagnetic wave transmission microloop antenna 41 and the electromagnetic wave reception microloop antenna 42 on the substrate side, and ◇ indicates the electromagnetic wave transmission microloop antenna on the conduction noise suppression layer side. 41 and the electromagnetic decoupling micro-loop antenna 42 measured by placing the electromagnetic wave receiving micro-loop antenna 42, □ represents the electromagnetic wave transmitting micro-loop antenna 41 and the electromagnetic wave receiving micro-loop antenna 42 arranged on the same side of the copper foil surface. The measured internal decoupling rate 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 substrate having a thickness of 1.0 mm (shear elastic modulus at 25 ° C. of skin layer binder: 1.7 × 10 ⁶ Pa) was obtained. On the skin layer of this substrate, a Ni-based soft magnetic metal of 10 nm in terms of film thickness was physically vapor deposited by the opposed target type magnetron sputtering method to form a composite layer, thereby obtaining a conduction noise suppressing body. At this time, the substrate temperature 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 portion of the conduction noise suppression layer of the obtained conduction noise suppression body was thinned with a microtome, and 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 conduction noise suppression body, 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 attenuation) measured from the substrate side when the incident electromagnetic wave amount is set as a reference (0), and ● indicates S ₂₁ (transmission attenuation) measured from the substrate side. ◇ 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 substrate side, and ◇ indicates the loss power ratio evaluated from the conduction noise suppression layer side.
In FIG. 20, ◯ indicates the mutual decoupling rate measured by arranging the electromagnetic wave transmission microloop antenna 41 on the substrate side, and ◇ indicates the mutual measurement measured by arranging the electromagnetic wave transmission microloop antenna 41 on the conduction noise suppression layer side. The symbol □ indicates the mutual decoupling rate measured by placing the electromagnetic wave transmitting micro loop antenna 41 and the electromagnetic wave receiving micro loop antenna 42 with the copper foil sandwiched therebetween.
In FIG. 21, ◯ indicates the internal decoupling ratio measured by arranging the electromagnetic wave transmission microloop antenna 41 and the electromagnetic wave reception microloop antenna 42 on the substrate side, and ◇ indicates the electromagnetic wave transmission microloop antenna on the conduction noise suppression layer side. 41 and the electromagnetic decoupling micro-loop antenna 42 measured by placing the electromagnetic wave receiving micro-loop antenna 42, □ represents the electromagnetic wave transmitting micro-loop antenna 41 and the electromagnetic wave receiving micro-loop antenna 42 arranged on the same side of the copper foil surface The measured internal decoupling rate is shown.

(Comparative Example 1)
The conductive noise suppression effect and radiation noise suppression effect of the substrate before the formation of the conductive noise suppression layer in Example 1 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.

Example 4
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 a Ni-based soft magnetic metal having a thickness of 20 nm on the obtained multilayer film silicone rubber by the opposed target type magnetron sputtering method. Got. 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 portion of the conduction noise suppression layer of the obtained conduction noise suppression body was thinned with a microtome, and 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 conduction noise suppression body, 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 ratio 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 2)
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 and 2 and FIGS. 10 to 29, the conduction noise suppression bodies 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 −1 dB or more, and the internal decoupling ratio is −1 dB or more, and it was confirmed that the conduction noise suppression effect and the radiation noise suppression effect are excellent. Also, when the internal decoupling rate is measured from the substrate side, compared to the case where the internal decoupling rate is measured from the conduction noise suppression layer side, the internal decoupling rate is the same as that of the metallic soft magnetic material of the conduction noise suppression layer. Due to the synergistic effect with the electromagnetic wave absorbing material, the substrate side was more than 10% better than 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.
Further, in Example 4, a conductive noise suppression layer was formed by vapor-depositing a Ni-based soft magnetic metal on a binder by a counter target type magnetron sputtering method, and the loss power ratio at 1 GHz was 0.3 or more. There was a good conduction noise suppression effect.

  Since the conductive noise suppressor of the present invention is a thin and light conductive noise suppressor having a conductive noise suppression function, it is possible to cope with recent downsizing, weight reduction, and multi-functionalization of electronic parts and electrical devices. It becomes.

It is a schematic sectional drawing which shows an example of the conduction noise suppression body of this invention. It is a schematic sectional drawing which shows the other example of the conduction noise suppression body of this invention. It is a schematic sectional drawing which shows the other example of the conduction noise suppression body of this invention. It is a high-resolution transmission electron microscope image of the conduction noise suppression layer in the conduction noise suppression body of this 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 conduction noise suppression body 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. Transmission noise suppression of S ₁₁ of Example 1 is a graph showing the (return loss) and S ₂₁ (transmission attenuation). It is a graph which shows the loss power ratio of the conduction noise suppression body of Example 1. It is a graph which shows the mutual decoupling rate of the conduction noise suppression body of Example 1, and copper foil. It is a graph which shows the internal decoupling rate of the conduction noise suppression body of Example 1, and copper foil. Transmission noise suppression of 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 conduction noise suppression body of Example 2. It is a graph which shows the mutual decoupling rate of the conduction noise suppression body of Example 2, and copper foil. It is a graph which shows the internal decoupling rate of the conduction noise suppression body of Example 2, and copper foil. Transmission noise suppression of S ₁₁ of Example 3 is a graph showing the (return loss) and S ₂₁ (transmission attenuation). It is a graph which shows the loss power ratio of the conduction noise suppression body of Example 3. It is a graph which shows the mutual decoupling rate of the conduction noise suppression body of Example 3, and copper foil. It is a graph which shows the internal decoupling rate of the conduction noise suppression body of Example 3, and copper foil. 6 is a graph showing S ₁₁ (reflection attenuation amount) and S ₂₁ (transmission attenuation amount) of a base body of Comparative Example 1; 6 is a graph showing a loss power ratio of a base body of Comparative Example 1. It is a graph which shows the mutual decoupling rate of the base | substrate of Comparative Example 1, and copper foil. It is a graph which shows the internal decoupling rate of the base | substrate of Comparative Example 1, and copper foil. Transmission noise suppression of S ₁₁ of Example 4 is a graph showing the (return loss) and S ₂₁ (transmission attenuation). It is a graph which shows the loss power ratio of the conduction noise suppression body of Example 4. It is a graph which shows the mutual decoupling rate of the conduction noise suppression body of Example 4, and copper foil. It is a graph which shows the internal decoupling rate of the conduction noise suppression body of Example 4, and copper foil.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Conduction noise suppression body 2 Base | substrate 3 Conduction noise suppression layer 10 Conduction noise suppression body 20 Conduction noise suppression body

Claims (6)

A substrate containing a binder;
A conductive noise suppression layer formed by integrating a part of the binder of the substrate and a metallic soft magnetic material containing one or more elements selected from the group consisting of iron, cobalt and nickel. Conductive noise suppressor. The conductive noise suppression layer is a layer in which a metallic soft magnetic material is dispersed in a binder having a shear modulus of 1 × 10 ³ to 1 × 10 ⁷ Pa by physical vapor deposition. The conduction noise suppressor according to claim 1.   The conductive noise suppressor according to claim 1 or 2, wherein the conductive noise suppression layer has a thickness of 0.005 to 0.3 µm.   The conduction noise suppressor according to any one of claims 1 to 3, wherein the binder is an organic polymer.   The conductive noise suppression body according to any one of claims 1 to 4, wherein the conductive noise suppression layer 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 of the wiring circuit in the electronic component or A conductive noise countermeasure method, wherein the conductive noise is disposed so as to be electromagnetically coupled to a conductor of a wiring circuit on a printed circuit board. 6. The conduction noise countermeasure method according to claim 5, wherein 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.

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