JP2017050427A - Electromagnetic wave shielding film, and electronic component mounting board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electromagnetic wave shielding film capable of shielding up to the electromagnetic waves of high frequency band by absorption while reducing the weight and thickness, and to provide an electronic component mounting board where an electronic component mounted on the board is coated with an electromagnetic wave shielding layer by using such an electromagnetic wave shielding film.SOLUTION: An electromagnetic wave shielding film 10 includes an electromagnetic wave shielding layer 3 including a first layer 31 containing metallic particles including at least one kind of metal and metal oxide, and a second layer 32 not containing the metallic particles. This electromagnetic wave shielding layer 3 coats an electronic component while placing the second layer 32 on the side of the electronic component mounted on the board. Since the second layer 32 is interposed between the first layer 31 and the electronic component, the clearance of the first layer 31 and electronic component is set to 10-200 μm.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an electromagnetic wave shielding film and an electronic component mounting substrate.

  Conventionally, electronic components that are easily affected by electromagnetic waves, such as mobile phones and medical devices, exothermic electronic components such as semiconductor elements, various electronic components such as capacitors and coils, or these electronic components are mounted on a circuit board. In order to reduce the influence of noise caused by electromagnetic waves, an electromagnetic shielding film has been attached to the surface of the electronic devices.

  As such an electromagnetic wave shielding film, for example, a film having a protective layer (base material layer) made of an insulating material and a metal layer laminated on one or both surfaces of the protective layer has been developed (for example, , See Patent Document 1).

  However, as described in Patent Document 1, when the electromagnetic wave shielding film has a configuration having a metal layer, there is a problem that it is not possible to cope with the reduction in weight and thickness that has been increasingly demanded in recent years.

  In addition, as described above, the electronic equipment to which the electromagnetic wave shielding film is attached has been diversified, and the frequency of electromagnetic waves, which is noise to be blocked, has also been diversified accordingly. However, the function of blocking such electromagnetic waves is demonstrated. Examples of the electromagnetic wave blocking layer that can be used include a reflective layer and an absorbing layer.

  Here, in the reflection layer, the electromagnetic wave incident on the electromagnetic wave blocking layer is blocked (shielded), and in the absorbing layer, the electromagnetic wave incident on the electromagnetic wave blocking layer is absorbed and converted into thermal energy, thereby converting the electromagnetic wave. Disappear and block. Among these, the reflective layer has a drawback that the reflected electromagnetic waves have an adverse effect such as malfunction on other members not covered with the electromagnetic wave shielding layer. Therefore, in recent years, research has been conducted on an electromagnetic wave shielding layer composed of an absorbing layer, and in particular, an electromagnetic shielding film including an electromagnetic wave shielding layer (absorbing layer) capable of effectively blocking even a high frequency band has been developed. ing.

JP 2006-156946 A

  An object of the present invention is to reduce the weight and thickness of the electromagnetic wave shielding film capable of blocking even electromagnetic waves in a high frequency band by absorption, and an electron mounted on a substrate using the electromagnetic wave shielding film. An object of the present invention is to provide an electronic component mounting substrate in which the component is covered with an electromagnetic wave shielding layer.

Such an object is achieved by the present invention described in the following (1) to (12).
(1) An electromagnetic wave shielding layer including a first layer containing metal-based particles containing at least one of a metal and a metal oxide, and a second layer not containing the metal-based particles,
The electromagnetic wave shielding layer covers the electronic component with the second layer facing the electronic component mounted on the substrate.
Since the second layer is interposed between the first layer and the electronic component, the separation distance between the first layer and the electronic component is 10 μm or more and 200 μm or less. An electromagnetic wave shielding film characterized by comprising:

  (2) The electromagnetic wave shielding film according to (1), wherein the electromagnetic wave shielding layer has a mismatch loss of 3 dB or less when measured using a microstripline method in an electromagnetic wave having a frequency of 0.1 GHz to 3 GHz. .

  (3) The electromagnetic wave shielding layer described in (1) or (2) above, wherein the electromagnetic wave shielding effect when measured using the KEC method (electric field) in an electromagnetic wave having a frequency of 0.01 GHz or more and 1 GHz or less is 30 dB or more. Electromagnetic shielding film.

  (4) The electromagnetic wave shielding film according to any one of (1) to (3), wherein the second layer includes at least one of a conductive polymer and a binder resin.

  (5) The electromagnetic shielding film according to (4), wherein the conductive polymer is at least one of polyaniline, PEDOT / PSS, polypyrrole, and polythiophene.

  (6) The electromagnetic shielding material according to any one of (1) to (5), wherein the metal-based particles are at least one of silver, copper, iron, nickel and aluminum, or an alloy containing these. the film.

  (7) Any of the above (1) to (6), wherein the first layer further includes a binder resin, and the content of the metal-based particles in the first layer is 60 wt% or more and 80 wt% or less. The film for electromagnetic wave shielding as described in crab.

  (8) The electromagnetic wave shielding film according to any one of (1) to (7), wherein the first layer has an average layer thickness of 10 μm to 1000 μm.

  (9) The electromagnetic wave shielding film according to any one of (1) to (8), wherein the second layer has an average layer thickness of 10 μm to 200 μm.

  (10) The electromagnetic wave shielding film according to any one of (1) to (9), wherein the electromagnetic wave shielding film further includes a protective sheet laminated on the first layer side of the electromagnetic wave shielding layer.

  (11) The electromagnetic wave shielding film according to any one of (1) to (10), wherein the electromagnetic wave shielding film has a light transmittance of 0.01% to 30% at a wavelength of 300 nm to 800 nm.

(12) An electronic component mounting substrate having a substrate, an electronic component mounted on the substrate, and an electromagnetic wave shielding layer that covers the substrate and the electronic component from the side of the substrate on which the electronic component is mounted Because
The electromagnetic wave shielding layer includes a first layer containing metal-based particles containing at least one of a metal and a metal oxide, and a second layer not containing the metal-based particles, Since the second layer is interposed between the layer and the electronic component, the separation distance between the first layer and the electronic component is 10 μm or more and 200 μm or less. Electronic component mounting board.

  In the present invention, the electromagnetic wave shielding film includes an electromagnetic wave including a first layer containing metal-based particles containing at least one of a metal and a metal oxide, and a second layer not containing the metal-based particles. A shielding layer, and the electromagnetic wave shielding layer covers the electronic component with the second layer facing the electronic component mounted on the substrate, whereby the first layer and the electron The second layer is interposed between the component and the separation distance between the first layer and the electronic component is 10 μm or more and 200 μm or less.

  According to the present invention having such a configuration, the mismatch loss when the electromagnetic wave shielding film is measured using the microstrip line method in electromagnetic waves having a frequency of 0.1 GHz or more and 3 GHz or less is 3 dB or less. The electromagnetic wave shielding effect when measured using the KEC method (electric field) in an electromagnetic wave of .01 GHz or more and 1 GHz or less can be 3 dB or more. Therefore, it can be said that the electromagnetic wave shielding film is reduced in weight and thickness, and effectively shields the electromagnetic wave by absorption by the electromagnetic wave shielding layer.

It is a longitudinal cross-sectional view which shows embodiment of the film for electromagnetic wave shields of this invention. It is a longitudinal cross-sectional view for demonstrating the 1st coating method of the coating method of the electronic component using the film for electromagnetic wave shielding shown in FIG. It is a longitudinal cross-sectional view for demonstrating the 2nd coating method of the coating method of the electronic component using the electromagnetic wave shielding film shown in FIG. It is a longitudinal cross-sectional view for demonstrating the 3rd coating method of the coating method of the electronic component using the film for electromagnetic wave shielding shown in FIG. It is a graph which shows the relationship between the frequency of electromagnetic waves at the time of measuring using a microstrip line method, and mismatch loss. It is a graph which shows the relationship between the frequency of electromagnetic waves when measured using the KEC method (electric field) and the shielding effect.

  Hereinafter, an electromagnetic wave shielding film and an electronic component mounting substrate of the present invention will be described in detail based on preferred embodiments shown in the accompanying drawings.

  The electromagnetic wave shielding film 10 of the present invention comprises a first layer 31 containing metal particles containing at least one of a metal and a metal oxide, and a second layer 32 not containing the metal particles. The electromagnetic wave shielding layer 3 includes an electromagnetic wave shielding layer 3 that covers the electronic component 4 with the second layer 32 facing the electronic component 4 mounted on the substrate 5. That the second layer 32 is interposed between the layer 31 and the electronic component 4 so that the separation distance between the first layer 31 and the electronic component is 10 μm or more and 200 μm or less. Features.

  According to the electromagnetic wave shielding film 10 having such a configuration, the mismatch loss when the electromagnetic wave shielding film is measured using the microstrip line method in an electromagnetic wave having a frequency of 0.1 GHz or more and 3 GHz or less is 3 dB or less. The electromagnetic wave shielding effect when measured using the KEC method (electric field) in electromagnetic waves having a frequency of 0.01 GHz to 1 GHz can be 30 dB or more. That is, it can be said that the electromagnetic wave shielding film 10 is light and thin, and can effectively block electromagnetic waves by absorbing the electromagnetic wave through the electromagnetic wave blocking layer 3.

Hereinafter, the electromagnetic wave shielding film will be described.
<Electromagnetic wave shielding film>
FIG. 1 is a longitudinal sectional view showing an embodiment of an electromagnetic wave shielding film of the present invention. In the following description, for convenience of description, the upper side in FIG. 1 is referred to as “upper” and the lower side is referred to as “lower”.

  The electromagnetic wave shielding film 10 is an electromagnetic wave shielding film used for covering the irregularities 6 on the substrate 5.

  As shown in FIG. 1, in this embodiment, the electromagnetic wave shielding film 10 includes a protective layer (protective sheet) 1 and an electromagnetic wave blocking layer 3 including a first layer 31 and a second layer 32. The electromagnetic wave shielding layer 3 is laminated on the lower surface (one surface) of the protective layer 1 in contact with the first layer 31 facing the protective layer 1 side.

  In the following description, the electronic component 4 is mounted (placed) on the substrate 5, and the unevenness 6 including the convex portions 65 and the concave portions 66 is formed on the substrate 5 by mounting the electronic component 4. The case where 6 is covered with the electromagnetic wave shielding film 10 will be described. That is, the case where the electronic component 4 mounted on the substrate 5 is covered with the electromagnetic wave shielding film 10 will be described. Examples of the electronic component 4 mounted on the substrate 5 include an LCD driver IC mounted on a flexible circuit board (FPC), an IC + capacitor around the touch panel, or an electronic circuit board (motherboard).

Hereinafter, the layers 1 and 3 included in the electromagnetic wave shielding film 10 will be described.
<Protective layer 1>
First, the protective layer 1 will be described.

  The protective layer (protective sheet) 1 has a function of preventing deterioration of the electromagnetic wave shielding layer 3 due to oxidation. Furthermore, the protective layer 1 has flexibility, and in the attaching step of the electronic component coating method described later, the electromagnetic wave shielding layer 3 is pushed into the unevenness 6 on the substrate 5 by using the electromagnetic wave shielding film 10. When covering this unevenness | corrugation 6, it functions as a protective (buffer) material which prevents the electromagnetic wave blocking layer 3 that has been pressed from breaking.

  The constituent material of the protective layer 1 is not particularly limited. For example, syndiotactic polystyrene, polymethylpentene, polybutylene terephthalate, polyethylene terephthalate, polypropylene such as non-axially oriented polypropylene and biaxially oriented polypropylene, cyclic olefin polymers, Examples thereof include resin materials such as silicone, styrene elastomer resin, and styrene butadiene rubber. Among these, it is preferable to use non-axially stretched polypropylene. Thereby, the protection property with respect to the electromagnetic wave shielding layer 3 of the protective layer 1 and also the heat resistance can be improved.

  The storage elastic modulus of the protective layer 1 at normal temperature (25 ° C.) is preferably 2.0E + 02 to 5.0E + 10 Pa, more preferably 2.0E + 03 to 5.0E + 09 Pa, and 2.0E + 04 to 3. More preferably, it is 0E + 09 Pa. Thus, by setting the storage elastic modulus at normal temperature (25 ° C.) of the protective layer 1 within the above range, it can be said that the protective layer 1 has flexibility, and an electromagnetic shielding film. 10, when the unevenness 6 on the substrate 5 is covered, the electromagnetic wave shielding layer 3 can be pushed in a state corresponding to the shape of the unevenness 6 without causing the electromagnetic wave shielding layer 3 to break. As a result, the substrate 5 provided with the unevenness 6 is covered with the electromagnetic wave blocking layer 3 in which the occurrence of breakage is prevented, following the shape of the unevenness 6. The electromagnetic wave shielding (blocking) property to the substrate 5 provided with the unevenness 6 is improved.

  Although the thickness of the protective layer 1 is not specifically limited, It is preferable that they are 3 micrometers or more and 20 micrometers or less, It is more preferable that they are 5 micrometers or more and 15 micrometers or less, More preferably, they are 7 micrometers or more and 12 micrometers or less. When the thickness of the protective layer 1 is less than the lower limit value, the protective layer 1 and thus the electromagnetic wave shielding layer 3 may be broken, and the electromagnetic shielding property may be deteriorated. Further, when the thickness of the protective layer 1 exceeds the upper limit, depending on the design of the substrate 5 covered with the electromagnetic wave shielding film 10, the weight and thickness of the laminate in which the substrate 5 is covered with the electromagnetic wave shielding film 10 can be reduced. May not be realized.

  Furthermore, the protective layer 1 may include a pressure-sensitive adhesive layer on the surface on the electromagnetic wave shielding layer 3 side. That is, the electromagnetic wave shielding layer 3 may be bonded to the protective layer 1 via the pressure-sensitive adhesive layer. Thereby, the adhesiveness (adhesiveness) of the protective layer 1 and the electromagnetic wave shielding layer 3 is improved.

  This pressure-sensitive adhesive layer is mainly composed of, for example, a pressure-sensitive adhesive made of at least one of an acrylic pressure-sensitive adhesive, a silicone pressure-sensitive adhesive, and a rubber-based pressure-sensitive adhesive.

  Examples of the acrylic pressure-sensitive adhesive include resins composed of (meth) acrylic acid and esters thereof, (meth) acrylic acid and esters thereof, and unsaturated monomers copolymerizable therewith (for example, vinyl acetate). , Styrene, acrylonitrile and the like) and the like. Moreover, what mixed 2 or more types of these resin is mentioned.

  Among these, one or more selected from the group consisting of methyl (meth) acrylate, ethylhexyl (meth) acrylate and butyl (meth) acrylate, and hydroxyethyl (meth) acrylate and vinyl acetate A copolymer with one or more selected is preferred. Thereby, control of adhesiveness and adhesiveness with the electromagnetic wave shielding layer 3 to which the adhesive layer adheres becomes easy.

  In this case, the pressure-sensitive adhesive layer has a urethane acrylate, an acrylate monomer, a polyvalent isocyanate compound (for example, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate), etc. in order to control adhesiveness (adhesiveness). Monomers and oligomers such as isocyanate compounds may be included.

  Examples of rubber-based adhesives include natural rubber-based, isoprene rubber-based, styrene-butadiene-based, recycled rubber-based, and polyisobutylene-based rubbers, and rubbers such as styrene-isoprene-styrene and styrene-butadiene-styrene. The thing etc. which mainly have the block copolymer containing are mentioned.

  Furthermore, examples of the silicone-based pressure-sensitive adhesive include dimethylsiloxane-based and diphenylsiloxane-based ones.

  The pressure-sensitive adhesive contained in the pressure-sensitive adhesive layer may be either a curable type or a non-curable type, but in the case of a curable type, a crosslinking agent may be added to the pressure-sensitive adhesive layer. Examples of the crosslinking agent include epoxy compounds, isocyanate compounds, metal chelate compounds, metal alkoxides, metal salts, amine compounds, hydrazine compounds, aldehyde compounds, and the like.

  In the case of the curable type, a photopolymerization initiator that cures the pressure-sensitive adhesive layer by irradiation with light such as ultraviolet rays may be added to the pressure-sensitive adhesive layer. Examples of the photopolymerization initiator include methoxyacetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2,2-diethoxyacetophenone, 2-methyl-1- [4- (methylthio) -phenyl]- Acetophenone compounds such as 2-morpholinopropane-1, benzophenone compounds, benzoin compounds, benzoin isobutyl ether compounds, benzoin methyl benzoate compounds, benzoin benzoic acid compounds, benzoin methyl ether compounds, benzylfinyl sulfide compounds Compounds, benzyl compounds, dibenzyl compounds, diacetyl compounds and the like.

  Furthermore, the adhesive layer has a rosin resin, terpene resin, coumarone resin, phenol resin, styrene resin, aliphatic petroleum resin, aromatic petroleum resin, aliphatic aromatic for the purpose of increasing its adhesive strength and shear strength. A tackifier such as a petroleum petroleum resin may be added.

  In addition, various additives such as a plasticizer, a tackifier, a thickener, a filler, an anti-aging agent, an antiseptic, an antifungal agent, a dye, and a pigment are added to the adhesive layer as necessary. May be.

<Electromagnetic wave blocking layer 3>
Next, the electromagnetic wave blocking layer (blocking layer) 3 will be described.

  The electromagnetic wave shielding layer 3 includes an electronic component 4 provided on the substrate 5, and other electronic components located on the opposite side of the substrate 5 (electronic component 4) via the electromagnetic wave shielding layer 3. It has a function of blocking (shielding) electromagnetic waves generated from one side, and in particular, has a function of blocking electromagnetic waves generated from the electronic component 4 more effectively.

  Here, in order to exert the function of blocking the electromagnetic wave, as described above, the reflection layer that blocks (shields) the electromagnetic wave incident on the electromagnetic wave blocking layer and the electromagnetic wave incident on the electromagnetic wave blocking layer are absorbed. Absorbing layers that are shielded (shielded) by the above are known.

  In such a reflection layer and an absorption layer, assuming that they have almost the same electromagnetic shielding properties, the absorption layer absorbs electromagnetic waves incident on the absorption layer and converts them into thermal energy. The electromagnetic wave is extinguished by this absorption. Therefore, from the standpoint that it is possible to reliably prevent the reflected electromagnetic wave, such as the reflective layer, from adversely affecting the other members that are not covered with the electromagnetic wave blocking layer. The layer is preferably composed of an absorbent layer.

  As an example of the electromagnetic wave shielding layer for which such characteristics are required, there is a configuration containing metal-based particles containing at least one of a metal and a metal oxide. However, it is known that the electromagnetic wave blocking layer having such a configuration generally has excellent blocking properties, but is superior in properties as a reflective layer that blocks electromagnetic waves by reflecting them. Therefore, the present inventor has studied a configuration in which such an electromagnetic wave blocking layer exhibits superior properties as an absorbing layer that blocks by absorbing electromagnetic waves while having excellent blocking properties. As a result, it has been found that in the electromagnetic wave blocking layer having the configuration containing the metal particles, the distance from the electronic component that generates the electromagnetic wave is related to the reflection or absorption of the electromagnetic wave.

  Then, the inventor conducted further earnest studies on the relationship between the distance between the electromagnetic wave shielding layer and the electronic component and the absorption of the electromagnetic wave, and as a result, increased the distance between the electromagnetic wave shielding layer and the electronic component. Specifically, it has been found that by setting the separation distance to 10 μm or more, it is possible to provide an absorption layer that shields electromagnetic waves by absorption rather than reflection. Moreover, it discovered that it could implement | achieve by setting the said separation distance to 200 micrometers or less from a viewpoint of achieving weight reduction and thickness reduction of an electromagnetic wave shielding layer (electromagnetic wave shielding film).

  Therefore, as shown in FIG. 1, the electromagnetic wave shielding layer 3 includes a first layer 31 containing metal-based particles containing at least one of a metal and a metal oxide, and a second layer not containing the metal-based particles. The second layer 32 is placed on the electronic component 4 side to cover the electronic component 4, and the second layer 32 is disposed between the first layer 31 and the electronic component 4. By interposing, the separation distance between the first layer 31 and the electronic component 4 is configured to be 10 μm or more and 200 μm or less, thereby reducing the weight and thickness of the electromagnetic wave shielding layer 3 (electromagnetic wave shielding film). The present invention has been completed since the electromagnetic wave blocking layer 3 can exert its function as an absorbing layer preferentially.

  By the way, a microstrip line method (MSL method) is known as a method for evaluating whether the electromagnetic wave incident on the electromagnetic wave blocking layer is blocked by reflecting or by blocking the electromagnetic wave. ing.

The MSL technique measured using, for example, according to IEC standard 62333-2, the microstrip line having a 50Ω impedance, using a network analyzer to measure the reflected component _{S 11} and the transmission component _{S 21} Is done.

Of these, the reflection component S ₁₁ is measured as a voltage (amplitude) intensity of the reflected wave with respect to the incident wave expressed in dB. Then, by using the reflection component S _11, the following equation (1) can be obtained mismatching loss representing the power strength of the non-reflected components with respect to an incident wave in dB.
Mismatch loss _{= -10 · log {1-10 ^ (} 2S 11/10)} [dB] (1)

  Components other than the reflection component in the mismatch loss include an absorption component and a transmission component. Therefore, it can be said that the reflection component increases when the mismatch loss value increases, and the absorption component and transmission component increase when the mismatch loss value decreases.

  Therefore, assuming that the transmission component is small, it can be said that the absorption component is large if the mismatch loss value is small. The reason why the reflection component is reduced is presumed that the impedance change on the circuit is reduced by the electromagnetic wave blocking layer, thereby suppressing the reflection in the circuit.

  Therefore, in the present invention, the mismatch loss when measured using the microstrip line method for electromagnetic waves having a frequency of 0.1 GHz to 3 GHz is preferably 3 dB or less, and more preferably 2 dB or less. With such an electromagnetic wave blocking layer, it can be said that the value of mismatch loss in electromagnetic waves in a high frequency band is small, and when the transmission component is small, the absorption component is large. It can be said that the blocking layer 3 is composed of an absorption layer.

  In addition to the MSL method described above, a KEC method developed by the Kansai Electronics Industry Promotion Center is known as a method for evaluating the blocking of electromagnetic waves incident on the electromagnetic wave blocking layer.

  Here, according to the KEC method, the electromagnetic shielding property for blocking electromagnetic waves is based on the characteristics of the measurement method described below, and absorbs (absorbs components) that blocks by absorbing electromagnetic waves and reflects by blocking electromagnetic waves. It is measured as a value obtained by adding the property (reflection component).

  In other words, this KEC method is a method for evaluating the shielding effect of electromagnetic waves generated in the near field separately for electric and magnetic fields, and the measurement using this method was transmitted from a transmitting antenna (transmission jig). It can be carried out by receiving electromagnetic waves with a receiving antenna (receiving jig) through an electromagnetic wave blocking layer 3 (measurement sample) in the form of a sheet. In such a KEC method, electromagnetic waves are blocked at the receiving antenna. The electromagnetic wave passing through (transmitting) the layer 3 is measured, that is, how much the transmitted electromagnetic wave (signal) is attenuated on the receiving antenna side by the electromagnetic wave blocking layer 3, so that the electromagnetic wave is blocked (shielded). The electromagnetic wave shielding property to be obtained is obtained in a state in which both a reflection component that reflects electromagnetic waves and an absorption component that absorbs electromagnetic waves are combined.

  Therefore, the electromagnetic wave shielding layer 3 preferably has an electromagnetic wave shielding effect of 30 dB or more when measured using the KEC method (electric field) in electromagnetic waves having a frequency of 0.01 GHz or more and 1 GHz or less, and 40 dB or more and 80 dB or less. It is more preferable that it is. Such an electromagnetic wave blocking layer 3 can be said to block high-frequency electromagnetic waves with high accuracy, and this electromagnetic wave blocking layer can be said to be a blocking layer that blocks absorption and reflection components.

  Accordingly, when the electromagnetic wave shielding layer has an inconsistency loss of 3 dB or less when measured using the microstrip line method in an electromagnetic wave having a frequency of 0.1 GHz to 3 GHz, the electromagnetic wave has a frequency of 0.01 GHz to 1 GHz. If the electromagnetic shielding effect when measured using the KEC method (electric field) is 30 dB or more, that is, the mismatch loss value measured using the MSL method is small in the electromagnetic wave shielding layer 3. If the electromagnetic wave shielding property (absorption component + reflection component) measured using the KEC method (electric field) is increased, the electromagnetic wave blocking layer 3 is reduced in the reflection component and transmission component in the reduced state. It can be said that it is an absorption layer that shields electromagnetic waves predominantly.

  As described above, in the present invention, such an electromagnetic wave shielding layer 3 does not contain the first layer 31 containing metal-based particles including at least one of metal and metal oxide, and the metal-based particles. The second layer 32 is laminated, and the second layer 32 is placed on the electronic component 4 side to cover the electronic component 4. The second layer 32 is interposed between the first layer 31 and the electronic component 4 so that the separation distance between the first layer 31 and the electronic component 4 is 10 μm or more and 200 μm or less. Has been.

  Hereinafter, the first layer 31 and the second layer 32 constituting the electromagnetic wave shielding layer 3 will be described.

(First layer)
The first layer 31 contains metal-based particles containing at least one of a metal and a metal oxide, thereby causing the electromagnetic wave blocking layer 3 to function as a blocking layer that blocks electromagnetic waves. It is.

Examples of the metal-based particles include metals such as gold, silver, copper, iron, nickel and aluminum, or alloys containing these, and AFe ₂ O ₄ (where A is Mn, Co, Ni, Cu Or a metal oxide such as ITO, ATO, FTO, etc., which can be used alone or in combination of two or more thereof.

  The average particle size of the metal-based particles is preferably 1.0 μm or more and 10.0 μm or less, and more preferably 4.5 μm or more and 7.5 μm or less. Thereby, the metal-based particles can be uniformly dispersed in the first layer 31. Therefore, the first layer 31 can exhibit the characteristics as this uniformly.

  Furthermore, the first layer 31 preferably contains a binder resin in addition to the metal-based particles as a constituent material. Thereby, since metal-type particle | grains can be disperse | distributed more uniformly in the 1st layer 31, the 1st layer 31 can be made to exhibit the characteristic as the 1st layer 31 uniformly. In addition, the conductive material can be easily set to a target content, so that the function as the first layer 31 can be surely exhibited.

  In addition, as the binder resin, various resin materials can be used and are not particularly limited. For example, epoxy resins, phenol resins, amino resins, unsaturated polyester resins, thermosetting resins such as thermosetting elastomers, acrylic resins, Examples include thermoplastic resins such as polyester resins, vinyl chloride resins, styrene resins, styrene thermoplastic elastomers, thermoplastic elastomers such as olefin thermoplastic elastomers, and one or more of these are used in combination. be able to.

  Further, the content of the metal particles in the first layer 31 is preferably 60 wt% or more and 80 wt% or less, and more preferably 65 wt% or more and 75 wt% or less. Thereby, the second layer 32 is interposed between the first layer 31 and the electronic component 4 while the first layer 31 is surely exhibiting the function as an electromagnetic wave blocking layer, so that the first layer 31 is provided. When the distance between the electronic component 4 and the electronic component 4 is set within a range of 10 μm or more and 200 μm or less, the electromagnetic wave blocking layer 3 can reliably exhibit the function as an absorbing layer that blocks electromagnetic waves by absorption.

  Furthermore, the average layer thickness T1 of the first layer 31 is not particularly limited, but is preferably 10 μm or more and 1000 μm or less, and more preferably 50 μm or more and 500 μm or less. When the thickness of the first layer 31 is less than the lower limit, depending on the constituent material of the first layer 31, there is a possibility of breaking at the end of the board-mounted component. Moreover, when the thickness of the 1st layer 31 exceeds the said upper limit, depending on the constituent material of the 1st layer 31, etc., there exists a possibility that shape followability may be insufficient. Further, even when the thickness T1 is within such a range, excellent electromagnetic shielding properties can be exhibited, so that the thickness T1 of the first layer 31 can be reduced, and the electromagnetic wave blocking layer 3 on the substrate 5 can be realized. It is possible to reduce the weight of the electronic component mounting board on which the electronic component 4 covered with is mounted.

(Second layer)
The second layer 32 does not contain the metal-based particles, and is interposed between the first layer 31 and the electronic component 4 when the electronic component 4 is covered, whereby the first layer It functions as a spacer for setting the separation distance between 31 and the electronic component 4 to 10 μm or more and 200 μm or less. Since such a second layer 32 is interposed, the separation distance between the first layer 31 and the electronic component 4 is set within an appropriate range. Therefore, the use of the first layer 31 as an absorption layer for blocking electromagnetic waves by absorption can be achieved.

  Such a second layer 32 may have any configuration as long as it does not contain the metal-based particles and does not contain a metal and a metal oxide. And those containing at least one of binder resins. Here, when the insulating property is ensured by the electronic component 4 itself covered with the electromagnetic wave shielding layer 3, the second layer 32 preferably contains both the conductive polymer and the binder resin. . Since the electromagnetic wave blocking layer containing a conductive polymer is generally known to exhibit a function as an absorbing layer that blocks electromagnetic waves by absorption, the second layer 32 is configured as described above. By doing so, the second layer 32 can exhibit not only a function as a spacer but also a function as an absorption layer. Moreover, when the insulating property is not ensured by the electronic component 4 itself, the second layer 32 is preferably made of a binder resin. That is, it is preferable that it is comprised independently by the resin material. By configuring the second layer 32 to have such a configuration, when the plurality of electronic components 4 are mounted on the substrate 5, the electronic components 4 can be reliably insulated from each other by the second layer 32. it can. Therefore, the second layer 32 can reliably exhibit not only a function as a spacer but also a function as an insulating layer.

  When the second layer 32 contains a conductive polymer and a binder resin, the content of the conductive polymer in the second layer 32 may be 20 wt% or more and 60 wt% or less. Preferably, it is 30 wt% or more and 50 wt% or less. Thereby, the function as an absorption layer can be reliably exhibited by the second layer 32.

  Examples of the conductive polymer include polyacetylene, polypyrrole, PEDOT (poly-ethylenedioxythiophene), PEDOT / PSS, polythiophene, polyaniline, poly (p-phenylene), polyfluorene, polycarbazole, polysilane, and derivatives thereof. These can be used alone or in combination of two or more. Among these, polyaniline, PEDOT / PSS, polypyrrole and polythiophene are preferable. According to these, the effect acquired by using the conductive polymer mentioned above can be exhibited more notably.

  As the binder resin, the same resin as that described in the first layer 31 can be used.

  In addition, although the separation distance of the 1st layer 31 and the electronic component 4 should just be 10 micrometers or more and 200 micrometers or less, it is preferable that they are 20 micrometers or more and 100 micrometers or less, and it is more preferable that they are 30 micrometers or more and 70 micrometers or less. Thereby, the effect mentioned above can be exhibited more notably.

  The average layer thickness T2 of the second layer 32 is such that the second layer 32 functions as a spacer, and the separation distance between the first layer 31 and the electronic component 4 is set within the above range. Further, it is set to the same size as the separation distance to be set, and may be 10 μm or more and 200 μm or less.

  In addition, as for the electromagnetic wave shielding layer 3, it is preferable that the storage elastic modulus in 150 degreeC is 1.0E + 05-1.0E + 09Pa, and it is more preferable that it is 5.0E + 05-5.0E + 08Pa. By setting the storage elastic modulus within such a range, the electromagnetic wave shielding layer 3 is pushed into the irregularities 6 on the substrate 5 by the pressing force from the protective layer 1 after the heating of the electromagnetic wave shielding film 10 in the attaching step. Thus, when the unevenness 6 is covered, the electromagnetic wave shielding layer 3 can be deformed corresponding to the shape of the unevenness 6 according to the pressing force from the protective layer 1. That is, the shape followability of the electromagnetic wave shielding layer 3 with respect to the unevenness 6 can be improved.

  When the electromagnetic wave shielding film 10 includes the protective layer 1 and the electromagnetic wave shielding layer 3 having the above-described configuration, the electromagnetic wave shielding film 10 can be reduced in weight and thickness.

The electromagnetic wave shielding film 10 preferably has a light transmittance of 0.01% or more and 30% or less at a wavelength of 300 nm or more and 800 nm or less, more preferably 0.01% or more and 10% or less. . As a result, it is possible to absorb and block light and to hide the inside covered with the electromagnetic wave shielding layer 3, that is, the electronic component 4, so that, for example, at the time of distribution of the electronic component mounting substrate coated with the electromagnetic wave shielding layer 3 The advantage that the secrecy of the electronic component 4 can be secured is obtained.
In addition, the said light transmittance can be calculated | required with an ultraviolet visible spectrophotometer, for example.

<Method of coating electronic parts>
(First coating method)
Using the electromagnetic wave shielding film 10 having the above configuration, for example, the electronic component 4 mounted on the substrate 5 is covered as follows.

  FIG. 2 is a longitudinal sectional view for explaining a first coating method of the electronic component coating method using the electromagnetic wave shielding film shown in FIG.

  The following first covering method for electronic parts has a sticking step of sticking the electromagnetic shielding film 10 on the substrate 5 so that the second layer 32 provided in the electromagnetic wave shielding layer 3 and the electronic parts 4 are adhered. .

(Attaching process)
As shown in FIG. 2A, in the present embodiment, the affixing step is performed so that the electromagnetic shielding film 10 follows the unevenness 6 provided by mounting the electronic component 4 on the substrate 5. It is a process of sticking.

  Although it does not specifically limit as a method of sticking following the unevenness | corrugation 6, For example, the following methods are mentioned.

  That is, first, the substrate 5 and the electromagnetic wave shielding film 10 are arranged so that the surface of the substrate 5 on which the unevenness 6 is formed and the surface of the electromagnetic wave shielding film 10 on the second layer 32 side face each other. These are set in a superposed state, and thereafter, these are pressed by applying pressure so that the electromagnetic wave shielding film 10 and the substrate 5 approach each other uniformly from the electromagnetic wave shielding film 10 side at room temperature.

  Thus, by uniformly pressing from the electromagnetic wave shielding film 10 side, the protective layer 1 follows the shape of the irregularities 6, and in addition to this, the electromagnetic wave blocking located on the substrate 5 side than the protective layer 1. Layer 3 also follows the shape of irregularities 6. Thereby, the unevenness 6 is covered with the protective layer 1 and the electromagnetic wave shielding layer 3 in a state where the protective layer 1 and the electromagnetic wave shielding layer 3 follow the shape of the unevenness 6.

  In such a pasting step, the temperature to be pasted is normal temperature, specifically, preferably 5 ° C. or higher and 35 ° C. or lower, more preferably 20 ° C. or higher and 30 ° C. or lower, more preferably 25 ° C. More preferably.

  The pressure to be applied is not particularly limited, but is preferably 0.05 MPa or more and 0.5 MPa or less, more preferably 0.1 MPa or more and 0.3 MPa or less.

  Furthermore, the sticking time is not particularly limited, but is preferably 1 second or longer and 60 seconds or shorter, more preferably 5 seconds or longer and 30 seconds or shorter.

  By setting the conditions in the pasting step within the above range, the electromagnetic wave shielding layer 3 follows the unevenness 6 on the substrate 5 without causing damage to the electronic component 4 due to pressurization from the electromagnetic wave shielding film 10 side. In this state, the unevenness 6 can be reliably covered with the electromagnetic wave shielding layer 3.

  By passing through the above processes, it can coat | cover so that the unevenness | corrugation 6 may follow with the protective layer 1 and the electromagnetic wave shielding layer 3. FIG. In the covering method in which the protective layer 1 remains on the coated unevenness 6 as in the present embodiment, insulation that insulates the electromagnetic wave blocking layer 3 from other members (such as electronic components) located on the opposite side of the substrate 5. The protective layer 1 exhibits the function as a layer.

(Second coating method)
Further, the electronic component 4 may be coated so as to cover the electronic component 4 without following the unevenness 6 in addition to the above-described method of covering the unevenness 6 with the electromagnetic wave shielding film 10.

  FIG. 3 is a longitudinal sectional view for explaining a second coating method of the electronic component coating method using the electromagnetic wave shielding film shown in FIG.

  The following second electronic component coating method is similar to the first coating method, in which the electromagnetic wave shielding film 10 is applied on the substrate 5 so that the second layer 32 and the electronic component 4 are adhered. Have

(Attaching process)
In this pasting step, as shown in FIG. 3A, in this embodiment, the electromagnetic wave shielding film 10 is pasted on the unevenness 6 provided by mounting the electronic component 4 on the substrate 5 without following it. To do.

  In order to attach without following the irregularities 6, for example, from the electromagnetic wave shielding film 10 side so that the electromagnetic wave shielding film 10 and the substrate 5 come close to each other in the attaching step described in the first covering method. This can be realized by setting the pressurizing condition when pressurizing uniformly. That is, by setting the pressurizing condition lower than the pressure when following the unevenness 6 and setting the pressure condition shorter than the time when following the unevenness 6, the electromagnetic wave shield without following the unevenness 6. The film 10 for use can be affixed.

  By such a coating method, the unevenness 6 is covered by the protective layer 1 and the electromagnetic wave shielding layer 3 in a state where the protective layer 1 and the electromagnetic wave shielding layer 3 do not follow the shape of the unevenness 6.

  In addition, when the electromagnetic wave shielding film 10 does not follow the shape of the unevenness 6 as described above, the formation of the protective layer 1 that functions as a protective (buffer) material that prevents the electromagnetic wave shielding layer 3 from breaking may be omitted. it can.

(Third coating method)
Furthermore, the coating of the electronic component 4 is a method of coating with the electromagnetic wave shielding film 10, that is, the first coating method of coating with the protective layer 1 and the electromagnetic wave shielding layer 3, and the protective layer from the electromagnetic wave shielding film 10. 1 may be peeled off and the electronic component 4 may be covered with the electromagnetic wave shielding layer 3.

  FIG. 4 is a longitudinal sectional view for explaining a third coating method of the electronic component coating method using the electromagnetic wave shielding film shown in FIG.

  The third electronic component covering method described below includes a step of attaching the electromagnetic wave shielding film 10 on the substrate 5 so that the second layer 32 and the electronic component 4 are adhered, and protection after the application step. A peeling step for peeling the layer 1.

(Attaching process)
As shown in FIG. 4A, the attaching step is provided by mounting the electronic component 4 on the substrate 5, as in the electronic component covering method (first covering method) described in FIG. The electromagnetic wave shielding film 10 is attached to the unevenness 6 so as to follow.

(Peeling process)
In the peeling step, for example, as shown in FIG. 4B, the protective layer 1 is peeled from the electromagnetic shielding film 10 after the pasting step.

  By this peeling process, in this embodiment, peeling occurs at the interface between the protective layer 1 and the electromagnetic wave shielding layer 3 (first layer 31) in the electromagnetic wave shielding film 10, and as a result, from the electromagnetic wave shielding layer 3 to the protective layer. 1 is peeled off. Accordingly, the unevenness 6 is covered with the electromagnetic wave shielding layer 3 in a state where the protective layer 1 is peeled off from the electromagnetic wave shielding layer 3.

  In addition, although it does not specifically limit as a method of peeling the protective layer 1, For example, peeling by manual work is mentioned.

  In this manual peeling, first, one end portion of the protective layer 1 is gripped, the protective layer 1 is peeled off from the electromagnetic wave shielding layer 3 from the gripped end portion, and then further from the end portion to the central portion. The protective layer 1 is peeled from the electromagnetic wave shielding layer 3 by sequentially peeling the protective layer 1 to the other end.

  By passing through the above processes, the unevenness | corrugation 6 can be coat | covered with the electromagnetic wave shielding layer 3 in the state which peeled the protective layer 1 from the electromagnetic wave shielding layer 3. FIG. According to such a coating method, it is possible to further reduce the weight and thickness when the electromagnetic wave blocking layer 3 blocks the electromagnetic wave.

  Further, the second coating method and the third coating method may be combined. That is, after pasting the electromagnetic wave shielding film 10 on the unevenness 6 without following it, the protective layer 1 is peeled off from the electromagnetic shielding film 10, and the electromagnetic wave blocking layer 3 not following the unevenness 6 makes the electronic component 4. You may make it coat | cover.

  In addition, in the said embodiment, as shown in FIG. 1, although the case where the protective layer 1 with which the film 10 for electromagnetic wave shielding was comprised was comprised by 1 layer, it is not limited to the thing of this structure, For example, protection The layer 1 may be a two-layer stack in which the first layer and the second layer are stacked in this order, or the first layer, the second layer, and the third layer in this order. It may be a laminated body of three layers.

  When it is set as the structure of a 2 layer laminated body, the thing of the structure similar to the protective layer 1 demonstrated in the said embodiment can be used as a 1st layer.

  The second layer is located between the first layer and the electromagnetic wave shielding layer 3, and in the first step of the method for producing the electromagnetic wave shielding film, the protective layer (protective sheet) 1 is applied to the electromagnetic wave shielding layer 3. When pasting, the first layer functions as an adhesive layer that adheres (sticks) to the electromagnetic wave shielding layer 3.

  Although this 2nd layer is not specifically limited, For example, it forms using various adhesive agents, such as an epoxy adhesive, an acrylic adhesive, a polyimide adhesive, and a cyanate adhesive.

  The thickness T (C) of the second layer is not particularly limited, but is preferably 1 μm or more and 10 μm or less, and more preferably 3 μm or more and 8 μm or less. When the thickness of the second layer is less than the lower limit, depending on the type of the constituent material of the second layer, there is a possibility that the adhesiveness due to the second layer is not sufficiently exhibited. When the thickness of the second layer exceeds the upper limit, depending on the design of the substrate 5 covered with the electromagnetic wave shielding film 10, the weight of the laminate in which the substrate 5 is covered with the electromagnetic wave shielding film 10 can be reduced. Thinning may not be realized.

  Furthermore, when it is set as the structure of a 3 layer laminated body, the thing of the structure similar to the protective layer 1 demonstrated in the said embodiment can be used as a 1st layer and a 3rd layer.

  When the electromagnetic wave shielding layer 3 is pushed into the unevenness 6 on the substrate 5 using the protective layer 1 as a push-in protection in the attaching step of the electronic component coating method, the second layer is It has a cushion function for pushing (embedding) into the irregularities 6. In addition, the second layer has a function of causing the pushing force to uniformly act on the third layer and further on the electromagnetic wave shielding layer 3 through the third layer. The electromagnetic wave blocking layer 3 can be pushed into the unevenness 6 with excellent sealing properties without generating a void between the blocking layer 3 and the unevenness 6.

  Examples of the constituent material of the second layer (cushion layer) include α-olefin polymers such as polyethylene and polypropylene, and α-olefins having ethylene, propylene, butene, pentene, hexene, methylpentene, and the like as copolymer components. Engineering plastics resins such as copolymer, polyethersulfone, polyphenylene sulfide, etc., may be used singly or in combination. Among these, it is preferable to use an α-olefin copolymer. Specifically, a copolymer of α-olefin such as ethylene and (meth) acrylic acid ester, a copolymer of ethylene and vinyl acetate, a copolymer of ethylene and (meth) acrylic acid (EMMA), And a partial ion cross-linked product thereof. Since the α-olefin copolymer is excellent in shape followability and further excellent in flexibility as compared with the constituent material of the third layer, the third layer is formed in the second layer composed of the constituent material. A cushion function for pushing (embedding) the layer into the unevenness 6 can be surely imparted.

  The thickness T (C) of the second layer is not particularly limited, but is preferably 10 μm or more and 100 μm or less, more preferably 20 μm or more and 80 μm or less, and further preferably 30 μm or more and 60 μm or less. . When the thickness of the second layer is less than the lower limit value, the shape followability of the second layer is insufficient, and the followability to the unevenness 6 may be insufficient in the thermocompression bonding step. In addition, when the thickness of the second layer exceeds the upper limit, in the thermocompression bonding process, the resin is more likely to be smeared out from the second layer, and adheres to the hot platen of the crimping apparatus, thereby reducing workability. There is a fear.

  The average linear expansion coefficient of the second layer at 25 to 150 ° C. is preferably 500 or more [ppm / ° C.], more preferably 1000 or more [ppm / ° C.]. By setting the average linear expansion coefficient of the second layer within such a range, the second layer has more excellent stretchability than the third layer when the electromagnetic wave shielding film 10 is heated. Can be made easy with stuff. Therefore, the shape followability of the second layer and the electromagnetic wave shielding layer 3 with respect to the unevenness 6 can be improved more reliably.

  Further, in the above-described embodiment, the unevenness is formed on the substrate by mounting the electronic component on the substrate, and the case where the unevenness is covered with the electromagnetic wave shielding film has been described. The coating is not limited to such unevenness, and for example, it may be applied to a flat region provided in a housing or the like.

  The electromagnetic shielding film and the electronic component mounting substrate of the present invention have been described above, but the present invention is not limited to these.

  For example, an arbitrary layer capable of exhibiting the same function may be added to the electromagnetic wave shielding film of the present invention and the electronic component mounting substrate of the present invention.

  EXAMPLES Hereinafter, although this invention is demonstrated in detail based on an Example, this invention is not limited to this.

Example 1
<Manufacture of film for evaluating electromagnetic shielding properties>
First, as a resin material for forming the first layer included in the electromagnetic wave shielding layer, polyaniline (trade name: PANT, manufactured by Regulus Co., Ltd.) as a conductive polymer and silver as metal particles are used. Spherical particles (trade name: Ag-XF301, manufactured by Fukuda Metal Foil Co., Ltd.) and polyester resin (trade name: Byron 63SS, manufactured by Toyobo Co., Ltd.) as a binder are 10% by weight: 70%: 20%. In addition, a styrene-based elastomer (manufactured by Toagosei Co., Ltd., product number: PPET-1501SG30) was prepared as a material for forming the second layer.

  Next, a polyethylene terephthalate film (manufactured by Teijin DuPont, A-314, thickness 38 μm) is prepared, coated with the resin material for forming the first layer, heated and dried, and then the first layer. Formed.

  Furthermore, on the polyethylene terephthalate film (Teijin DuPont, A-314, thickness 38 μm), 10 μm of the styrene elastomer (manufactured by Toagosei Co., Ltd., product number PPET-1501SG30) was coated, and then heated and dried. A second layer was formed.

  Next, the first layer and the second layer were laminated, and the polyethylene terephthalate film was peeled off to produce an electromagnetic wave shielding evaluation film.

  In the film for evaluating electromagnetic shielding properties of Example 1, the thickness of the second layer was 10 μm.

(Example 2)
The film for evaluating electromagnetic wave shielding properties of Example 2 in the same manner as in Example 1 except that the second layer was coated with 30 μm of a styrene elastomer (product number PPET-1501SG30 manufactured by Toagosei Co., Ltd.). Was made.

(Example 3)
The film for evaluating electromagnetic wave shielding properties of Example 3 in the same manner as in Example 1 except that the second layer was coated with 43 μm of a styrene elastomer (manufactured by Toagosei Co., Ltd., product number PPET-1501SG30). Was made.

Example 4
The film for evaluating electromagnetic shielding properties of Example 4 in the same manner as in Example 1 except that the second layer was coated with 63 μm of a styrene elastomer (manufactured by Toagosei Co., Ltd., product number PPET-1501SG30). Was made.

(Example 5)
First, as a resin material for forming the first layer included in the electromagnetic wave shielding layer, polyaniline (trade name: PANT, manufactured by Regulus Co., Ltd.) as a conductive polymer and silver as metal particles are used. Spherical particles (trade name: Ag-XF301, manufactured by Fukuda Metal Foil Co., Ltd.) and polyester resin (trade name: Byron 63SS, manufactured by Toyobo Co., Ltd.) as a binder are 10% by weight: 70%: 20%. Prepared to include.

  Next, a polyethylene terephthalate film (manufactured by Teijin DuPont, A-314, thickness 38 μm) is prepared, coated with the resin material for forming the first layer, heated and dried, and then the first layer. Formed.

  Furthermore, after laminating a PET core single-sided acrylic resin (manufactured by Niei Kaiko Co., Ltd., GL-5B) on the first layer, the polyethylene terephthalate film is peeled off, so that a 5 μm acrylic resin is formed on the first layer. A layer was formed. Thereafter, a 125 μm thick polyethylene terephthalate film (manufactured by Panac, Lumila-125S10) is laminated on the acrylic resin layer to evaluate the electromagnetic shielding properties of Example 5 including the second layer having a thickness of 130 μm. A film was prepared.

(Reference Example 1)
First, as a resin material for forming the first layer included in the electromagnetic wave shielding layer, polyaniline (trade name: PANT, manufactured by Regulus Co., Ltd.) as a conductive polymer and silver as metal particles are used. Spherical particles (trade name: Ag-XF301, manufactured by Fukuda Metal Foil Co., Ltd.) and polyester resin (trade name: Byron 63SS, manufactured by Toyobo Co., Ltd.) as a binder are 10% by weight: 70%: 20%. Prepared to include.

  Next, a polyethylene terephthalate film (manufactured by Teijin DuPont, A-314, thickness 38 μm) is prepared, coated with the resin material for forming the first layer, heated and dried, and then the first layer. Formed.

  Furthermore, after laminating a PET core single-sided acrylic resin (manufactured by Niei Kaiko Co., Ltd., GL-5B) on the first layer, the polyethylene terephthalate film is peeled off, so that a 5 μm acrylic resin is formed on the first layer. A layer was formed. Then, on this acrylic resin layer, a 125 μm thick polyethylene terephthalate film (Plumac Corp., Lumira-125S10) is laminated and laminated, whereby a second layer having a thickness of 255 μm is provided. A film for evaluating electromagnetic shielding properties was produced.

(Comparative Example 1)
After coating the resin-based material for forming the first layer on a polyethylene terephthalate film (manufactured by Teijin DuPont, A-314, thickness 38 μm), the coating is heated and dried to obtain a first 30 μm thick first What formed the layer as an electromagnetic wave shielding property evaluation film of Comparative Example 1, that is, an electromagnetic wave shielding property evaluation film composed of an electromagnetic wave shielding layer composed of the first layer in which the formation of the second layer is omitted. Produced.

(Comparative Example 2)
First, as a resin material for forming the first layer included in the electromagnetic wave shielding layer, polyaniline (trade name: PANT, manufactured by Regulus Co., Ltd.) as a conductive polymer and silver as metal particles are used. Spherical particles (trade name: Ag-XF301, manufactured by Fukuda Metal Foil Co., Ltd.) and polyester resin (trade name: Byron 63SS, manufactured by Toyobo Co., Ltd.) as a binder are 10% by weight: 70%: 20%. Prepared to include.

  Next, a polyethylene terephthalate film (manufactured by Teijin DuPont, A-314, thickness 38 μm) is prepared, coated with the resin material for forming the first layer, heated and dried, and then the first layer. Formed.

  Furthermore, after laminating the PET core single-sided acrylic resin (GL-5B, manufactured by Niei Kaiko Co., Ltd.) on the first layer, the polyethylene terephthalate film is peeled off, so that a 5 μm acrylic resin layer is formed as the second layer. A film for evaluating electromagnetic shielding properties of Comparative Example 2 provided was prepared.

<Evaluation test>
<< Inconsistency loss >>
Using the above-described microstrip line method, the value of mismatch loss in the frequency range of 0.1 to 10 GHz was measured for the films for evaluating electromagnetic shielding properties produced in each Example (Reference Example) and each Comparative Example. The maximum value of mismatch loss within the frequency range of 0.1 GHz to 3 GHz was determined.

<< Electromagnetic wave shielding properties >>
About the 1st layer with which the electromagnetic wave shielding layer used by each Example (reference example) and each comparative example is provided, the electromagnetic shielding effect in the range of frequency 0.001-1GHz is used using the KEC method (electric field) mentioned above. The value was measured, and the minimum value of the electromagnetic wave shielding effect within the frequency range of 0.01 GHz to 1 GHz was determined.

  Table 1 and FIGS. 5 and 6 show the results of the evaluation tests of the above Examples (Reference Examples) and Comparative Examples.

  As shown in Table 1, the thickness of the second layer is defined, and the separation distance between the electronic component that should block electromagnetic waves with the electromagnetic wave shielding film and the first layer is appropriately set within an appropriate range. Thus, as in each example, the mismatch loss when measured using the microstrip line method in an electromagnetic wave having a frequency of 0.1 GHz to 3 GHz could be set to 3 dB or less. Moreover, the electromagnetic wave shielding effect at the time of measuring using the KEC method (electric field) in the electromagnetic wave with a frequency of 0.01 GHz or more and 1 GHz or less by making the first layer contain metal-based particles is 30 dB or more. I was able to set it. From these facts, it was found that the electromagnetic wave shielding layer can shield the electromagnetic wave by the absorbing component and the reflective component in a state where the reflective component inside the substrate circuit is reduced.

DESCRIPTION OF SYMBOLS 10 Electromagnetic wave shielding film 1 Protective layer 3 Electromagnetic wave shielding layer 31 1st layer 32 2nd layer 4 Electronic component 5 Substrate 6 Concavity and convexity 65 Convex part 66 Concave part

Claims (12)

An electromagnetic wave shielding layer including a first layer containing metal-based particles containing at least one of a metal and a metal oxide, and a second layer not containing the metal-based particles;
The electromagnetic wave shielding layer covers the electronic component with the second layer facing the electronic component mounted on the substrate.
Since the second layer is interposed between the first layer and the electronic component, the separation distance between the first layer and the electronic component is 10 μm or more and 200 μm or less. An electromagnetic wave shielding film characterized by comprising:   The electromagnetic wave shielding film according to claim 1, wherein the electromagnetic wave shielding layer has a mismatch loss of 3 dB or less when measured using a microstripline method in an electromagnetic wave having a frequency of 0.1 GHz to 3 GHz.   The electromagnetic wave shielding film according to claim 1, wherein the electromagnetic wave shielding layer has an electromagnetic wave shielding effect of 30 dB or more when measured using the KEC method (electric field) in an electromagnetic wave having a frequency of 0.01 GHz to 1 GHz.   The electromagnetic wave shielding film according to any one of claims 1 to 3, wherein the second layer contains at least one of a conductive polymer and a binder resin.   The film for electromagnetic wave shielding according to claim 4, wherein the conductive polymer is at least one of polyaniline, PEDOT / PSS, polypyrrole, and polythiophene.   6. The electromagnetic wave shielding film according to claim 1, wherein the metal-based particles are at least one of silver, copper, iron, nickel and aluminum, or an alloy containing these. 6.   The first layer according to any one of claims 1 to 6, wherein the first layer further includes a binder resin, and the content of the metal-based particles in the first layer is 60 wt% or more and 80 wt% or less. Film for electromagnetic wave shielding.   The film for electromagnetic wave shielding according to claim 1, wherein the first layer has an average layer thickness of 10 μm or more and 1000 μm or less.   The electromagnetic wave shielding film according to claim 1, wherein the second layer has an average layer thickness of 10 μm or more and 200 μm or less.   The electromagnetic wave shielding film according to any one of claims 1 to 9, wherein the electromagnetic wave shielding film further includes a protective sheet laminated on the first layer side of the electromagnetic wave shielding layer.   The electromagnetic wave shielding film according to claim 1, wherein the electromagnetic wave shielding film has a light transmittance of 0.01% to 30% at a wavelength of 300 nm to 800 nm. An electronic component mounting substrate comprising: a substrate; an electronic component mounted on the substrate; and an electromagnetic wave shielding layer that covers the substrate and the electronic component from a side of the substrate on which the electronic component is mounted. ,
The electromagnetic wave shielding layer includes a first layer containing metal-based particles containing at least one of a metal and a metal oxide, and a second layer not containing the metal-based particles, Since the second layer is interposed between the layer and the electronic component, the separation distance between the first layer and the electronic component is 10 μm or more and 200 μm or less. Electronic component mounting board.

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