Electromagnetic wave shielding film, printed wiring board with electromagnetic wave shielding film, and method for producing same

Abstract

To provide: an electromagnetic wave-shield film which can prevent the occurrence of a trouble including the rupture or deformation of an insulative resin layer, an electromagnetic wave-shield layer or a print wiring board in thermocompression, and which can improve the workability because of satisfactory adhesion and electrical connectability which can be ensured even in a gentle press condition; an electromagnetic wave-shield film-attached print wiring board; and a manufacturing method thereof.SOLUTION: An electromagnetic wave-shield film 1 comprises: an insulative resin layer 10; a metal layer 22 adjacent to the insulative resin layer 10; and an anisotropic conductive adhesive layer 24 adjacent to the metal layer 22 on a side opposite to the insulative resin layer 10. The anisotropic conductive adhesive layer 24 contains thermally conductive particles 24b. The thermally conductive particles 24b are 40 MPa or less in 10%-compression strength.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an electromagnetic wave shielding film, a printed wiring board with an electromagnetic wave shielding film, and a method for producing the same. [Background technology]

[0002] In order to shield electromagnetic noise generated from a printed wiring board or from external electromagnetic noise, an electromagnetic shielding film having an insulating resin layer and an electromagnetic shielding layer may be provided on the surface of a printed wiring board via an insulating film (coverlay film) (see, for example, Patent Document 1). The electromagnetic shielding layer has, for example, a metal layer for shielding electromagnetic waves and a conductive adhesive layer for electrically connecting the metal layer to the printed circuit of the printed wiring board. The conductive adhesive layer contains a resin and conductive particles.

[0003] When providing the electromagnetic shielding film on the surface of the printed wiring board, the printed wiring board with the insulating film and the electromagnetic shielding film are overlapped so that the insulating film and the conductive adhesive layer are in contact with each other, and then they are thermocompression bonded. At this time, a part of the conductive adhesive layer of the electromagnetic shielding film contacts the printed circuit (ground) of the printed wiring board through the through hole formed in the insulating film, thereby electrically connecting the metal layer and the printed circuit of the printed wiring board. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2017-220592 A Summary of the Invention [Problem to be solved by the invention]

[0005] As the conductive particles, metal particles such as copper particles, silver particles, and copper particles coated with silver, which have high electrical conductivity, are used. In the conductive adhesive layer, a part of the conductive particles usually protrudes from the resin part. When the electromagnetic shielding film is thermocompression-bonded to the printed wiring board with the insulating film, in order to ensure sufficient adhesion, it is necessary to bring the resin of the conductive adhesive layer into contact with the printed wiring board with the insulating film. When metal particles are used as the conductive particles, the metal particles are hard and difficult to deform, so high pressing pressure, high pressing temperature, and long pressing time are required to bring the resin layer into contact with the printed wiring board with the insulating film.

[0006] However, if the pressing pressure or pressing temperature is high, defects such as breakage or deformation may occur in the insulating resin layer, the electromagnetic wave shielding layer, and the printed wiring board, and the electromagnetic wave shielding property may be reduced. In addition, if the pressing time is long, the workability decreases. Furthermore, in order to obtain excellent electromagnetic wave shielding property and electrical connectivity, the more the content of metal particles in the conductive adhesive layer, the better, but even if the pressing conditions are made strict, it tends to be difficult to ensure adhesion between the conductive adhesive layer and the printed wiring board with the insulating film.

[0007] The present invention aims to provide an electromagnetic wave shielding film, a printed wiring board with an electromagnetic wave shielding film, and a method for producing the same, which can ensure sufficient adhesion and electrical connectivity even under mild pressing conditions, thereby preventing defects such as breakage and deformation of an insulating resin layer, an electromagnetic wave shielding layer, or a printed wiring board during thermocompression bonding, and improving workability. [Means for solving the problem]

[0008] The present invention has the following aspects. [1] An insulating resin layer and an electromagnetic wave shielding layer adjacent to the insulating resin layer, the electromagnetic wave shielding layer contains conductive particles, An electromagnetic wave shielding film, wherein the conductive particles have a 10% compressive strength of 40 MPa or less. [2] The electromagnetic wave shielding film according to [1], wherein the conductive particles are resin particles with a conductive film, the surfaces of which are coated with a conductive film. [3] The electromagnetic wave shielding film according to [2], wherein the ratio of the mass of the conductive film to the total mass of the resin particles with the conductive film is 5 mass % or more and 50 mass % or less. [4] The electromagnetic wave shielding film according to [2] or [3], wherein the resin particles contain at least one resin selected from the group consisting of acrylic resin, urethane resin, nylon resin and silicone resin. [5] The electromagnetic shielding film according to any one of [2] to [4], wherein the conductive film has a specific gravity of 2.50 or more and 22.0 or less. [6] The electromagnetic wave shielding film according to any one of [1] to [5], wherein the conductive film contains at least one metal selected from the group consisting of gold, silver, and copper. [7] The electromagnetic shielding film according to any one of [2] to [6], wherein the conductive film contains two or more different metals. [8] The electromagnetic shielding film according to any one of [2] to [8], wherein the conductive film includes a sputtered film. [9] The electromagnetic shielding film according to any one of [2] to [8], wherein the conductive film includes a plating film.

[10] The electromagnetic wave shielding film according to any one of [1] to [9], wherein the conductive particles have a specific gravity of 1.00 or more and 3.00 or less.

[11] The electromagnetic shielding film according to any one of [1] to

[10] , wherein the conductive particles have an average particle size of 0.5 μm or more and 20 μm or less.

[12] The electromagnetic wave shielding layer has a metal layer adjacent to the insulating resin layer and a conductive adhesive layer adjacent to the metal layer on the opposite side to the insulating resin layer, The electromagnetic wave shielding film according to any one of [1] to

[11] , wherein the conductive adhesive layer contains the conductive particles.

[13] The conductive adhesive layer contains either one or both of a thermosetting resin and a thermoplastic resin, and the conductive particles; The electromagnetic wave shielding film according to

[12] , wherein the content of the conductive particles in the conductive adhesive layer is 0.20 mass % or more and 50 mass % or less with respect to the total mass of the conductive adhesive layer.

[14] The electromagnetic shielding film according to any one of [1] to

[13] , wherein the insulating resin layer has a thickness of 1.0 μm or more and 20 μm or less.

[15] A printed wiring board having a printed circuit on at least one side of a substrate; an insulating film adjacent to a surface of the printed wiring board on which the printed circuit is provided; an electromagnetic wave shielding film according to any one of [1] to

[14] , which is adjacent to the insulating film on the opposite side to the printed wiring board and in which the electromagnetic wave shielding layer is in contact with the insulating film; A printed wiring board with an electromagnetic wave shielding film.

[16] A printed wiring board having a printed circuit provided on at least one surface of a substrate and an insulating film provided with an insulating film adjacent to the surface of the printed wiring board on which the printed circuit is provided; [1] to

[14] and an electromagnetic wave shielding film, The insulating film and the electromagnetic wave shielding layer are overlapped so as to be in contact with each other, and then thermocompression bonded to each other. Effect of the Invention

[0009] According to the present invention, it is possible to provide an electromagnetic wave shielding film, a printed wiring board with an electromagnetic wave shielding film, and a manufacturing method thereof, which can ensure sufficient adhesion and electrical connectivity even under mild pressing conditions, thereby preventing defects such as breakage and deformation of an insulating resin layer, an electromagnetic wave shielding layer, or a printed wiring board during thermocompression bonding, and improving workability. [Brief description of the drawings]

[0010] [Figure 1] 1 is a cross-sectional view showing a first embodiment of an electromagnetic wave shielding film of the present invention. [Diagram 2] FIG. 2 is a cross-sectional view showing a second embodiment of the electromagnetic wave shielding film of the present invention. [Diagram 3] 1 is a cross-sectional view showing one embodiment of a printed wiring board with an electromagnetic wave shielding film of the present invention. [Figure 4] 4A to 4C are cross-sectional views showing a manufacturing process for the printed wiring board with the electromagnetic shielding film of FIG. [Diagram 5] FIG. 5(A) is a plan view showing a flexible printed wiring board with an insulating film for connectivity evaluation to measure the minimum connection diameter, FIG. 5(B) is a cross-sectional view taken along line AA in FIG. 5(A), and FIG. 5(C) is a cross-sectional view taken along line BB in FIG. 5(A). [Figure 6] FIG. 6(A) is a plan view showing a test piece used for measuring the minimum connection diameter, and FIG. 6(B) is a cross-sectional view taken along CC in FIG. 6(A). DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] The following definitions of terms apply throughout the specification and claims. The term "isotropically conductive adhesive layer" refers to a conductive adhesive layer that has conductivity in the thickness direction and the surface direction. The term "anisotropic conductive adhesive layer" refers to a conductive adhesive layer that has conductivity in the thickness direction but not in the surface direction. "Conductive adhesive layer with no conductivity in the surface direction" means a layer with a surface resistance of 1×10 4 It means a conductive adhesive layer having a resistance of Ω / □ or more. The average particle diameter of the conductive particles is determined by randomly selecting 30 particles from a microscopic image of the particles, measuring the minimum and maximum diameters of each particle, defining the median of the minimum and maximum diameters as the particle diameter of one particle, and then calculating the arithmetic mean of the measured particle diameters of the 30 particles. The specific gravity of the conductive particles is a value measured at a temperature of 23° C. in accordance with Method A of JIS K7112:1999. The 10% compressive strength of the conductive particles is determined from the results of measurement using a micro compression tester, according to the following formula (α). C(x)=2.48P / πd 2 (α) where C(x) is the 10% compressive strength (MPa), P is the test force at 10% displacement of the particle diameter (N), and d is the particle diameter (mm). The thickness of films (carrier films, release films, insulating films, etc.) and coatings (insulating resin layers, conductive adhesive layers, etc.) was measured at five randomly selected locations using a digital length measuring machine (Mitutoyo Corporation, Litematic VL-50-B) and was calculated by averaging the measured thickness. The thickness of the metal layer is the average value of thickness measurements taken at five randomly selected locations by X-ray fluorescence analysis in accordance with JIS K0119:2008. The storage modulus is calculated from the stress applied to the measurement object and the strain detected, and is measured as one of the viscoelastic properties using a dynamic viscoelasticity measuring device that outputs the value as a function of temperature or time. The surface resistance is a surface resistivity measured by a method conforming to JIS K 7194:1994, JIS R 1637:1998, and JIS K 6911:2006. The dimensional ratios in FIGS. 1 to 4 are different from the actual ones for the sake of convenience of explanation.

[0012] <Electromagnetic wave shielding film> A first aspect of the present invention is an electromagnetic wave shielding film having an insulating resin layer and an electromagnetic wave shielding layer adjacent to the insulating resin layer, the electromagnetic wave shielding layer containing specific conductive particles.

[0013] Fig. 1 is a cross-sectional view showing an electromagnetic wave shielding film 1 according to a first embodiment. Fig. 2 is a cross-sectional view showing an electromagnetic wave shielding film 1 according to a second embodiment. Both the electromagnetic wave shielding film 1 of the first embodiment and the second embodiment have an insulating resin layer 10, an electromagnetic wave shielding layer 20 adjacent to the insulating resin layer 10, a carrier film 30 adjacent to the insulating resin layer 10 on the side opposite the electromagnetic wave shielding layer 20, and a release film 40 adjacent to the electromagnetic wave shielding layer 20 on the side opposite the insulating resin layer 10. In the electromagnetic wave shielding film 1 of the first embodiment, the electromagnetic wave shielding layer 20 has a metal layer 22 adjacent to the insulating resin layer 10 and an anisotropic conductive adhesive layer 24 adjacent to the release film 40. In the electromagnetic wave shielding film 1 of the second embodiment, the electromagnetic wave shielding layer 20 has a metal layer 22 adjacent to the insulating resin layer 10 and an isotropic conductive adhesive layer 26 adjacent to the release film 40.

[0014] The thickness of the electromagnetic wave shielding film 1 (excluding the carrier film 30 and the release film 40) is preferably 3 μm or more and 50 μm or less, and more preferably 5 μm or more and 30 μm or less. If the thickness of the electromagnetic wave shielding film 1 excluding the carrier film 30 and the release film 40 is equal to or more than the lower limit of the above range, the film is unlikely to break when the carrier film 30 is peeled off. If the thickness of the electromagnetic wave shielding film 1 excluding the carrier film 30 and the release film 40 is equal to or less than the upper limit of the above range, the printed wiring board with the electromagnetic wave shielding film can be made thin.

[0015] (insulating resin layer) The insulating resin layer 10 becomes a protective layer for the metal layer 22 after the electromagnetic wave shielding film 1 is attached to the surface of an insulating film provided on the surface of a flexible printed wiring board and the carrier film 30 is peeled off from the electromagnetic wave shielding film 1.

[0016] Examples of the insulating resin layer 10 include a coating film formed by applying a paint containing a thermosetting resin and a curing agent and semi-curing or curing the paint; a coating film formed by applying a paint containing a thermoplastic resin and drying the paint; and a layer made of a film obtained by melt-molding a composition containing a thermoplastic resin. From the viewpoint of heat resistance during the solder reflow process, a coating film formed by applying a paint containing a thermosetting resin and a curing agent and semi-curing or curing the paint is preferred.

[0017] Examples of the thermosetting resin include amide resin, epoxy resin, phenol resin, amino resin, alkyd resin, urethane resin, synthetic rubber, ultraviolet-curable acrylate resin, etc. As the thermosetting resin, amide resin and epoxy resin are preferred from the viewpoint of excellent heat resistance. The curing agent may be any known curing agent suitable for the type of thermosetting resin. Examples of the thermoplastic resin include aromatic polyether ketone, polyimide, polyamide imide, polyamide, polysulfone, polyether sulfone, polyphenylene sulfone, polyphenylene sulfide, polyphenylene sulfide sulfone, and polyphenylene sulfide ketone.

[0018] The insulating resin layer 10 may contain either or both of a colorant (pigment, dye, etc.) and a filler in order to conceal the printed circuit of the printed wiring board or to impart design features to the printed wiring board with the electromagnetic wave shielding film. As either or both of the colorant and the filler, a pigment or a filler is preferred from the viewpoints of weather resistance, heat resistance, and hiding power, and from the viewpoints of hiding power and design of the printed circuit, a black pigment, a combination of a black pigment with another pigment, or a combination of a black pigment with a filler is more preferred. The insulating resin layer 10 may contain a flame retardant. The insulating resin layer 10 may contain other components as necessary within the range that does not impair the effects of the present invention.

[0019] The surface resistance of the insulating resin layer 10 is 1×10 6 The surface resistance of the insulating resin layer 10 is preferably 1×10 19 Ω / □ or less is preferable. The thickness of the insulating resin layer 10 is preferably 1.0 μm or more and 20 μm or less, more preferably 2.0 μm or more and 15 μm or less, and even more preferably 3.0 μm or more and 8.0 μm or less. If the thickness of the insulating resin layer 10 is 1.0 μm or more, the insulating resin layer 10 can fully function as a protective layer. If the thickness of the insulating resin layer 10 is 2.0 μm or more, the thickness variation in the surface of the insulating resin layer 10 can be suppressed, and performance and productivity can be improved. If the thickness of the insulating resin layer 10 is 3.0 μm or more, the insulating resin layer 10 becomes even less likely to break. If the thickness of the insulating resin layer 10 is 20 μm or less, the pressing conditions can be further relaxed. If the thickness of the insulating resin layer 10 is 15 μm or less, the conformability to the step of the printed wiring board is improved. If the thickness of the insulating resin layer 10 is 8.0 μm or less, the electromagnetic wave shielding film 1 can be made thin.

[0020] (electromagnetic wave shielding layer) The electromagnetic wave shielding layer 20 has a metal layer 22 and a conductive adhesive layer (anisotropic conductive adhesive layer 24 or an isotropic conductive adhesive layer 26) adjacent to the side of the metal layer 22 opposite the insulating resin layer 10, and therefore has sufficiently high electromagnetic wave shielding properties.

[0021] Metal layer: The metal layer 22 is a layer made of metal. The metal layer 22 is formed so as to extend in the planar direction, and therefore has electrical conductivity in the planar direction and functions as a layer that blocks electromagnetic waves, etc.

[0022] Examples of the metal layer 22 include a deposition layer formed by physical vapor deposition (vacuum deposition, sputtering, ion beam deposition, electron beam deposition, etc.) or CVD (chemical vapor deposition), a plating layer formed by plating, and a metal foil. In that the metal layer 22 can be made thin and has excellent electrical conductivity in the surface direction even when it is thin, the metal layer 22 is preferably a deposition layer or a plating layer. In that the metal layer 22 can be easily formed by a dry process, the metal layer 22 is more preferably a deposition layer, and a deposition layer formed by physical vapor deposition is even more preferable.

[0023] Examples of metals constituting the metal layer 22 include aluminum, silver, copper, gold, conductive ceramics, etc. Among these, silver or copper is preferable from the viewpoint of electrical conductivity. Among the metal layers 22, a metal vapor deposition layer is preferred because it has high electromagnetic wave shielding properties and is easy to form a thin metal film, and a silver vapor deposition layer or a copper vapor deposition layer is more preferred.

[0024] The surface resistance of the metal layer 22 is preferably 0.001 Ω / □ or more and 1 Ω / □ or less, and more preferably 0.001 Ω / □ or more and 0.5 Ω / □ or less. If the surface resistance of the metal layer 22 is equal to or more than the lower limit of the above range, the metal layer 22 can be made sufficiently thin. If the surface resistance of the metal layer 22 is 1 Ω / □ or less, the electromagnetic wave shielding properties can be sufficiently exhibited. If the surface resistance of the metal layer 22 is 0.5 Ω / □ or less, the effect on the transmission characteristics of the printed wiring board can be reduced.

[0025] The thickness of the metal layer 22 is preferably 0.01 μm or more and 5 μm or less, and more preferably 0.05 μm or more and 3 μm or less. When the thickness of the metal layer 22 is equal to or more than the lower limit of the above range, the effect of shielding electromagnetic noise is further improved. When the thickness of the metal layer 22 is equal to or less than the upper limit of the above range, the electromagnetic shielding film 1 can be made thinner. In addition, the productivity and flexibility of the electromagnetic shielding film 1 are improved.

[0026] Anisotropic conductive adhesive layer: The anisotropic conductive adhesive layer 24 has conductivity in the thickness direction, has no conductivity in the planar direction, and has adhesiveness. The anisotropic conductive adhesive layer 24 has the advantage that the amount of conductive-coated resin particles can be reduced, and as a result, the flexibility and adhesion of the electromagnetic wave shielding film 1 can be further improved, and costs can be reduced. Since the anisotropic conductive adhesive layer 24 has no conductivity in the planar direction, the electromagnetic wave shielding layer 20 has little effect on the transmission characteristics of the printed wiring board, making it possible to produce a printed wiring board with an electromagnetic wave shielding film having small transmission loss.

[0027] The anisotropic conductive adhesive layer 24 may be, for example, a layer made of a conductive adhesive. The anisotropic conductive adhesive layer 24 is preferably a thermosetting conductive adhesive layer containing a thermosetting resin 24a and conductive particles 24b, because it exhibits heat resistance after curing and is easy to maintain adhesion and electrical connection with the printed circuit of the printed wiring board during thermocompression bonding. The thermosetting anisotropic conductive adhesive layer 24 may be in an uncured state or in a B-stage state. In the present invention, in the conductive adhesive layer, a thermoplastic resin may be used instead of the thermosetting resin, or a thermosetting resin and a thermoplastic resin may be used in combination.

[0028] Examples of the thermosetting resin 24a include epoxy resin, phenol resin, amino resin, alkyd resin, urethane resin, synthetic rubber, and ultraviolet-cured acrylate resin. Epoxy resin is preferable because of its excellent heat resistance. The epoxy resin may contain a rubber component (nitrile rubber, acrylic rubber, etc.) for imparting flexibility, a tackifier, etc. The thermosetting resin 24a may contain other components (such as a curing agent, a curing accelerator, and a reaction initiator) as necessary, as long as the effects of the present invention are not impaired.

[0029] Examples of the thermoplastic resin used for the anisotropic conductive adhesive layer 24 include the same thermoplastic resins as those listed for the insulating resin layer 10. The anisotropic conductive adhesive layer 24 may contain cellulose resin and microfibril (glass fiber, etc.) in order to increase the strength and improve the punching characteristics of the anisotropic conductive adhesive layer 24. The anisotropic conductive adhesive layer 24 may contain other components (flame retardant, antiblocking agent, adhesion improver, dispersant, etc.) as necessary within a range that does not impair the effects of the present invention.

[0030] The 10% compressive strength of the conductive particles 24b is 40 MPa or less, preferably 0.25 MPa or more and 19.0 MPa or less, and more preferably 0.5 MPa or more and 7.0 MPa or less. If the 10% compressive strength of the conductive particles 24b is 19.0 MPa or less, the conductive particles 24b are easily deformed during thermocompression bonding. Therefore, even if the conditions such as the press pressure, press temperature, and press time during thermocompression bonding are not strict, the resin of the anisotropic conductive adhesive layer 24 is easily in contact with the printed wiring board with the insulating film, and sufficient adhesion can be ensured. As a result, defects such as breakage and deformation of the insulating resin layer 10, the metal layer 22, and the printed wiring board are suppressed, and the workability is also excellent. If the 10% compressive strength of the conductive particles 24b is 7.0 MPa or less, the adhesion is further improved. In addition, the workability is further improved by enabling pressure bonding even in a short press time. If the 10% compressive strength of the conductive particles 24b is 0.25 MPa or more, there is no risk of the anisotropic conductive adhesive layer 24 deforming during film formation and causing a decrease in performance. If the 10% compressive strength of the conductive particles 24b is 0.5 MPa or more, the anisotropic conductive adhesive layer 24 is likely to be reliably electrically connected to the printed circuit of the printed wiring board through the through holes of the insulating film without a significant loss of pressure applied to the metal layer 22 during thermocompression bonding.

[0031] The average particle diameter of the conductive particles 24b is preferably 1 μm or more and 20 μm or less, more preferably 2 μm or more and 15 μm or less, and even more preferably 3 μm or more and 10 μm or less. If the average particle diameter of the conductive particles 24b is 1 μm or more, it is easy to ensure the electrical connection of the electromagnetic wave shielding layer 20 to the printed circuit. If the average particle diameter of the conductive particles 24b is 3 μm or more, it is possible to make the anisotropic conductive adhesive layer thicker, suppressing the in-plane thickness fluctuation and stabilizing the performance and productivity. If the average particle diameter of the conductive particles 24b is equal to or less than the upper limit of the above range, it is possible to ensure the fluidity of the anisotropic conductive adhesive layer 24, and as described below, when the anisotropic conductive adhesive layer 24 is pressed into the through-hole of the insulating film, the through-hole of the insulating film can be sufficiently filled with the conductive adhesive.

[0032] As the conductive particles 24b, resin particles with a conductive film having a core-shell structure in which the surfaces of resin particles are covered with a conductive film are preferred, since it is easy to set the 10% compressive strength within the above range. Examples of the resin material of the resin particles include acrylic resin, urethane resin, nylon resin, silicone resin, etc. The resin material of the resin particles may be one type or two or more types. The resin particles preferably contain at least one type selected from the group consisting of acrylic resin, urethane resin, nylon resin, and silicone resin, because the resin particles are inexpensive and easily available, and resin particles having a narrow particle size range are easily manufactured. When the resin particles require heat resistance and solvent resistance, it is preferable to use crosslinked resin particles, and when flexibility is required, it is preferable to use uncrosslinked resin particles.

[0033] Examples of materials for the conductive film in the resin particles with a conductive film include gold, silver, copper, platinum, nickel, palladium, and aluminum. The conductive film preferably contains at least one metal selected from the group consisting of gold, silver, and copper, because this improves the conductivity of the conductive film and allows the electromagnetic wave shielding layer 20 to be more reliably electrically connected to the printed circuit. In order to improve the performance of the conductive film, the conductive film may contain two or more different metals. For example, in order to improve adhesion and uniformity, the conductive film may be formed by forming a metal film such as gold, silver, or copper on a nickel film as an anchor.

[0034] The conductive film in the resin particles with a conductive film is preferably a plated film or a vapor-deposited film because the resin particles with a conductive film having a core-shell structure can be easily manufactured. Among the vapor-deposited films, a sputtered film formed by sputtering such as barrel sputtering is more preferable because it is inexpensive.

[0035] The specific gravity of the conductive film is preferably 2.50 or more and 22.0 or less, more preferably 7.30 or more and 20.0 or less, and even more preferably 7.50 or more and 12.0 or less. If the specific gravity of the conductive film is 2.50 or more and 22.0 or less, the conductive film has excellent conductivity, the specific gravity of the conductive film-attached resin particles is kept low, and the conductive film-attached resin particles in the anisotropic conductive adhesive layer 24 are easily distributed uniformly, and the anisotropic conductive adhesive layer 24 can be easily manufactured. If the specific gravity of the conductive film is 7.30 or more and 20.0 or less, the conductive film has a further improved conductivity, so that the ratio of the mass of the conductive film to the total mass of the conductive film-attached resin particles 24b can be lowered to improve dispersibility, and the amount of the conductive film-attached resin particles 24b added can be reduced to improve adhesion. If the specific gravity of the conductive film is 7.50 or more and 12.0 or less, the conductive film-attached resin particles 24b can be easily manufactured.

[0036] The specific gravity of the resin particles with conductive film is preferably 1.00 or more and 3.00 or less, and more preferably 1.10 or more and 2.00 or less. When the specific gravity of the resin particles with conductive film is equal to or more than the lower limit of the above range, the conductivity is excellent. When the specific gravity of the conductive particles 24b is equal to or less than the upper limit of the above range, the 10% compressive strength is easily within the above range. In addition, the distribution of the resin particles with conductive film in the anisotropic conductive adhesive layer 24 can be made more uniform, and the metal layer 22 can be more reliably electrically connected to the printed circuit.

[0037] The ratio of the mass of the conductive film to the total mass of the resin particles with conductive film is preferably 2.5% by mass or more and 50% by mass or less, more preferably 4% by mass or more and 30% by mass or less, and even more preferably 5% by mass or more and 20% by mass or less. If the ratio of the mass of the conductive film is equal to or more than the lower limit of the above range, the conductivity of the resin particles with conductive film is improved, and the electromagnetic wave shielding layer 20 can be more reliably electrically connected to the printed circuit. If the ratio of the mass of the conductive film is equal to or less than the upper limit of the above range, the ratio of the resin particles can be relatively increased, and the 10% compressive strength can be easily set within the above range. In addition, the specific gravity of the resin particles with conductive film is kept low, and the concentration of the resin particles with conductive film in the anisotropic conductive adhesive layer 24 is less likely to be non-uniform, and the anisotropic conductive adhesive layer 24 can be easily manufactured.

[0038] The content of the conductive particles 24b in the anisotropic conductive adhesive layer 24 is preferably 0.2% by mass or more and 30% by mass or less, more preferably 0.4% by mass or more and 20% by mass or less, based on the total mass of the anisotropic conductive adhesive layer 24. When the content of the conductive particles 24b is equal to or more than the lower limit of the above range, the conductivity of the anisotropic conductive adhesive layer 24 is improved, and the electromagnetic shielding properties and electrical connectivity are improved. When the content of the conductive particles 24b is equal to or less than the upper limit of the above range, the adhesiveness and fluidity (ability to conform to the shape of the through holes in the insulating film) of the anisotropic conductive adhesive layer 24 are improved. In addition, the flexibility of the electromagnetic wave shielding film 1 is improved. In addition, the manufacturing cost of the electromagnetic wave shielding film 1 is reduced.

[0039] The storage modulus of the anisotropic conductive adhesive layer 24 at 180° C. is 1×10 3 Pa or more 5×10 7 Pa or less is preferable, and 5×10 3 Pa or more 1×10 7 Pa or less is more preferable. If the storage modulus of the anisotropic conductive adhesive layer 24 at 180°C is equal to or greater than the lower limit of the above range, the anisotropic conductive adhesive layer 24 will have a more appropriate hardness, and pressure loss in the anisotropic conductive adhesive layer 24 during thermocompression bonding can be reduced. As a result, the anisotropic conductive adhesive layer 24 and the printed circuit of the printed wiring board are sufficiently bonded, and the anisotropic conductive adhesive layer 24 is reliably electrically connected to the printed circuit of the printed wiring board through the through holes of the insulating film. If the storage modulus of the anisotropic conductive adhesive layer 24 at 180°C is equal to or greater than 5×10 7 If the storage modulus at 180° C. is 1×10 Pa or less, the flexibility of the electromagnetic shielding film 1 is improved. As a result, the electromagnetic shielding film 1 is easily sunk into the through-holes of the insulating film, and the anisotropic conductive adhesive layer 24 passes through the through-holes of the insulating film and is more reliably electrically connected to the printed circuit of the printed wiring board. 7 If the pressure is equal to or less than Pa, the conductive film-coated resin particles 24b can be easily deformed.

[0040] The surface resistance of the anisotropic conductive adhesive layer 24 is 1×10 4 Ω / □ or more 1×10 16 Ω / □ or less is preferable, 1×106 Ω / □ or more 1×10 14 Ω / □ or less is more preferable. If the surface resistance of the anisotropic conductive adhesive layer 24 is equal to or greater than the lower limit of the above range, the content of the conductive particles 24b can be kept low. In addition, the electromagnetic wave shielding layer 20 has a small effect on the transmission characteristics of the printed wiring board, and a printed wiring board with an electromagnetic wave shielding film having small transmission loss can be manufactured. If the surface resistance of the anisotropic conductive adhesive layer 24 is equal to or less than the upper limit of the above range, there is no practical problem with the anisotropy.

[0041] The thickness of the anisotropic conductive adhesive layer 24 is preferably 1 μm or more and 25 μm or less, and more preferably 2 μm or more and 15 μm or less. If the thickness of the anisotropic conductive adhesive layer 24 is 1 μm or more, the adhesion of the anisotropic conductive adhesive layer 24 can be ensured. If the thickness of the anisotropic conductive adhesive layer 24 is 2 μm or more, the in-plane thickness variation of the anisotropic conductive adhesive layer 24 can be suppressed, and performance and productivity can be stabilized. If the thickness of the anisotropic conductive adhesive layer 24 is equal to or less than the upper limit of the above range, the electromagnetic wave shielding film 1 can be made thinner. In addition, the flexibility of the electromagnetic wave shielding film 1 is improved.

[0042] Isotropic conductive adhesive layer: The isotropically conductive adhesive layer 26 is conductive in the thickness direction and in the surface direction, and also has adhesiveness. The isotropic conductive adhesive layer 26 has the advantage that the number of conductive paths is increased, resulting in high stability of electrical connection and higher electromagnetic shielding properties of the electromagnetic shielding film 1. In addition, by using the conductive particles 26b, the flexibility of the isotropic conductive adhesive layer 26 can be improved, and by reducing the ratio of metal components in the isotropic conductive adhesive layer 26, the effect of the electromagnetic shielding layer 20 on the transmission characteristics of the printed wiring board can be reduced.

[0043] The isotropic conductive adhesive layer 26 may be, for example, a layer made of a conductive adhesive. A thermosetting conductive adhesive layer containing a thermosetting resin 26a and conductive particles 26b is preferred because it can exhibit heat resistance after curing and is easy to maintain a conductive path during thermocompression bonding. The thermosetting resin 26a contained in the isotropic conductive adhesive layer 26 may be the same as the thermosetting resin 24a contained in the anisotropic conductive adhesive layer 24, and the preferred forms are also the same.

[0044] The range of 10% compressive strength of the conductive particles 26b is similar to the range of 10% compressive strength of the conductive particles 24b contained in the anisotropic conductive adhesive layer 24, and the preferred range is also similar. As the conductive particles 26b, like the conductive particles 24b contained in the anisotropic conductive adhesive layer 24, the above-mentioned conductive film-attached resin particles are preferred, and the preferred form of the conductive film-attached resin particles is also the same.

[0045] The average particle diameter of the conductive particles 26b in the isotropic conductive adhesive layer 26 is preferably 0.5 μm to 10 μm, more preferably 0.5 μm to 5 μm, and even more preferably 0.5 μm to 3 μm. If the average particle diameter of the conductive particles 26b is equal to or greater than the lower limit of the range, the manufacturing cost of the conductive particles 26b can be reduced. If the average particle diameter of the conductive particles 26b is equal to or less than the upper limit of the range, the number of contact points of the conductive particles 26b increases, and the conductivity in the three-dimensional direction can be stably improved.

[0046] The content of the conductive particles 26b in the isotropic conductive adhesive layer 26 is preferably 5% by mass or more and 60% by mass or less, and more preferably 9% by mass or more and 50% by mass or less, based on the total mass of the isotropic conductive adhesive layer 26. When the proportion of the conductive particles 26b is equal to or more than the lower limit of the above range, the conductivity of the isotropic conductive adhesive layer 26 is improved. When the proportion of the conductive particles 26b is equal to or less than the upper limit of the above range, the adhesion and fluidity (ability to conform to the shape of the through holes in the insulating film) of the isotropic conductive adhesive layer 26 are improved. In addition, the flexibility of the electromagnetic wave shielding film 1 is improved.

[0047] The storage modulus of the isotropic conductive adhesive layer 26 at 180° C. is 1×10 3 Pa or more 5×10 7 Pa or less is preferable, and 5×10 3 Pa or more 1×10 7The reason why the above range is preferable is the same as that for the anisotropic conductive adhesive layer 24.

[0048] The surface resistance of the isotropic conductive adhesive layer 26 is preferably 0.05 Ω / □ or more and 2.0 Ω / □ or less, more preferably 0.1 Ω / □ or more and 1.0 Ω / □ or less. If the surface resistance of the isotropic conductive adhesive layer 26 is equal to or more than the lower limit of the above range, the content of the conductive particles 26b is kept low, the viscosity of the conductive adhesive does not become too high, and the applicability is further improved. In addition, the fluidity of the isotropic conductive adhesive layer 26 (the ability to conform to the shape of the through holes of the insulating film) can be further ensured. If the surface resistance of the isotropic conductive adhesive layer 26 is equal to or less than the upper limit of the above range, the entire surface of the isotropic conductive adhesive layer 26 has uniform conductivity.

[0049] The thickness of the isotropic conductive adhesive layer 26 is preferably 1 μm or more and 20 μm or less, more preferably 2 μm or more and 17 μm or less, and even more preferably 4 μm or more and 15 μm or less. If the thickness of the isotropic conductive adhesive layer 26 is equal to or more than the lower limit of the above range, the conductivity of the isotropic conductive adhesive layer 26 is good, and the electromagnetic wave shielding property can be sufficiently exhibited. In addition, the fluidity (ability to follow the shape of the through-hole of the insulating film) of the isotropic conductive adhesive layer 26 can be ensured, the through-hole of the insulating film can be sufficiently filled with the conductive adhesive, and the adhesion can be ensured. If the thickness of the isotropic conductive adhesive layer 26 is equal to or less than the upper limit of the above range, the electromagnetic wave shielding film 1 can be made thin. In addition, the flexibility of the electromagnetic wave shielding film 1 is improved.

[0050] (Carrier film) The carrier film 30 is a support that reinforces and protects the insulating resin layer 10 and the electromagnetic wave shielding layer 20, and improves the handleability of the electromagnetic wave shielding film 1. In particular, when a film having a thickness of 10 μm or less is used as the insulating resin layer 10, the presence of the carrier film 30 can prevent the insulating resin layer 10 from breaking. The carrier film 30 is peeled off from the insulating resin layer 10 after the electromagnetic wave shielding film 1 is attached to a printed wiring board or the like.

[0051] The carrier film 30 used in this embodiment has a carrier film body 32 and a release agent layer 34 provided on the surface of the carrier film body 32 on the insulating resin layer 10 side.

[0052] Examples of the resin material of the carrier film body 32 include polyethylene terephthalate (hereinafter sometimes referred to as "PET"), polyethylene naphthalate, polyethylene isophthalate, polybutylene terephthalate, polyolefin, polyacetate, polycarbonate, polyphenylene sulfide, polyamide, ethylene-vinyl acetate copolymer, polyvinyl chloride, polyvinylidene chloride, synthetic rubber, liquid crystal polymer, etc. As the resin material, PET is preferable from the viewpoints of heat resistance (dimensional stability) during production of the electromagnetic wave shielding film 1 and cost.

[0053] The carrier film body 32 may contain either or both of a colorant (pigment, dye, etc.) and a filler. As either or both of the colorant and the filler, a color different from that of the insulating resin layer 10 is preferable so that it can be clearly distinguished from the insulating resin layer 10 and it is easy to notice any remaining part of the carrier film 30 after thermocompression bonding, and a white pigment, a filler, a combination of a white pigment and another pigment, or a combination of a white pigment and a filler is more preferable.

[0054] The storage modulus of the carrier film body 32 at 180° C. is 8×10 7 Pa or more 5×10 9 Pa or less is preferable, and 1×10 8 Pa or more 8×10 8Pa or less is more preferable. If the storage modulus of the carrier film main body 32 at 180°C is equal to or greater than the lower limit of the aforementioned range, the carrier film 30 will have appropriate hardness, which will reduce pressure loss in the carrier film 30 during thermocompression bonding and prevent breakage of the electromagnetic wave shielding film 1. If the storage modulus of the carrier film main body 32 at 180°C is equal to or less than the upper limit of the aforementioned range, the carrier film 30 will have good flexibility and the electromagnetic wave shielding film 1 will have improved ability to conform to steps on a printed wiring board.

[0055] The thickness of the carrier film body 32 is preferably 12 μm or more and 100 μm or less, and more preferably 20 μm or more and 75 μm or less. When the thickness of the carrier film body 32 is equal to or more than the lower limit of the above range, the handling properties of the electromagnetic shielding film 1 are good. When the thickness of the carrier film body 32 is equal to or less than the upper limit of the above range, heat is easily transferred to the conductive adhesive layer when the conductive adhesive layer of the electromagnetic shielding film 1 is thermocompression bonded to the surface of the insulating film. In addition, the ability of the electromagnetic shielding film 1 to conform to steps on a printed wiring board is improved.

[0056] The release agent layer 34 is formed by treating the surface of the carrier film body 32 with a release agent. By having the release agent layer 34 on the carrier film 30, when the carrier film 30 is peeled off from the insulating resin layer 10, the carrier film 30 is easily peeled off and the insulating resin layer 10 is less likely to break. As the release agent, a known release agent may be used.

[0057] The thickness of the release agent layer 34 is preferably 0.01 μm or more and 30 μm or less, and more preferably 0.05 μm or more and 20 μm or less. If the thickness of the release agent layer 34 is within the above range, the carrier film 30 becomes easier to peel off.

[0058] The thickness of the carrier film 30 is preferably 12 μm or more and 125 μm or less, and more preferably 25 μm or more and 100 μm or less. When the thickness of the carrier film 30 is equal to or more than the lower limit of the above range, the handling property of the electromagnetic shielding film 1 is good. When the thickness of the carrier film 30 is equal to or less than the upper limit of the above range, heat is easily transferred to the conductive adhesive layer when the conductive adhesive layer of the electromagnetic shielding film 1 is thermocompression bonded to the surface of the insulating film. In addition, the conformability of the electromagnetic shielding film 1 to steps of a printed wiring board is improved.

[0059] (Release film) The release film 40 protects the conductive adhesive layer and is effective in preventing blocking and improving sliding properties when the electromagnetic shielding film 1 is wound into a roll or cut into sheets and stacked. The release film 40 is peeled off from the conductive adhesive layer before the electromagnetic shielding film 1 is attached to a printed wiring board or the like.

[0060] The release film 40 has, for example, a release film body 42 and a release agent layer 44 provided on the surface of the release film body 42 on the conductive adhesive layer side.

[0061] The resin material of the release film body 42 may be the same as the resin material of the carrier film body 32 . The release film body 42 may contain a colorant, a filler, and the like. The thickness of the release film body 42 is preferably 5 μm or more and 500 μm or less, more preferably 10 μm or more and 150 μm or less, and even more preferably 20 μm or more and 100 μm or less.

[0062] The release agent layer 44 is formed by treating the surface of the release film body 42 with a release agent. By having the release agent layer 44 on the release film 40, when the release film 40 is peeled off from the conductive adhesive layer, the release film 40 is easily peeled off and the conductive adhesive layer is less likely to break. As the release agent, a known release agent may be used.

[0063] The thickness of the release agent layer 44 is preferably 0.01 μm or more and 30 μm or less, and more preferably 0.05 μm or more and 20 μm or less. If the thickness of the release agent layer 44 is within the above range, the release film 40 becomes even easier to peel off.

[0064] (Manufacturing method of electromagnetic wave shielding film) The electromagnetic wave shielding film 1 of the first embodiment can be produced by the following method (A1) or method (A2). The electromagnetic wave shielding film 1 of the second embodiment can be produced by the following method (B1) or method (B2).

[0065] The method (A1) is a method comprising the following steps (A1-1) to (A1-4). Step (A1-1): A step of forming an insulating resin layer 10 on one surface of a carrier film 30. Step (A1-2): A step of forming a metal layer 22 on the surface of the insulating resin layer 10 opposite to the carrier film 30 side. Step (A1-3): A step of forming an anisotropic conductive adhesive layer 24 on the surface of the metal layer 22 opposite to the insulating resin layer 10. Step (A1-4): A step of laminating a release film 40 on the surface of the anisotropic conductive adhesive layer 24 opposite to the metal layer 22. Each step of the method (A1) will be described in detail below.

[0066] The method for forming the insulating resin layer 10 in the step (A1-1) may be, for example, the following method. A method in which a coating material containing a thermosetting resin and a curing agent is applied to the surface of the carrier film 30 on the release agent layer 34 side, and then semi-cured or cured. A method in which a paint containing a thermoplastic resin is applied to the surface of the carrier film 30 on the release agent layer 34 side, and then dried. A method in which a film formed by extrusion molding of a composition containing a thermoplastic resin is directly laminated on the surface of the carrier film 30 on which the release agent layer 34 is formed. Among these methods, from the standpoint of heat resistance during soldering, etc., a method in which a paint containing a thermosetting resin and a curing agent is applied to the surface of the carrier film 30 on the release agent layer 34 side, and then semi-cured or cured, is preferred. Examples of a method for applying the coating material include methods using various coaters such as a die coater, a gravure coater, a roll coater, a curtain flow coater, a spin coater, a bar coater, a reverse coater, a kiss coater, a fountain coater, a rod coater, an air doctor coater, a knife coater, a blade coater, a cast coater, and a screen coater. When semi-curing or curing the thermosetting resin, it is sufficient to heat it using a heater such as a heater or an infrared lamp, or it may be irradiated with ultraviolet rays using an ultraviolet irradiator.

[0067] Examples of the method for forming the metal layer 22 in step (A1-2) include a method for forming a vapor-deposited film by physical vapor deposition or CVD (chemical vapor deposition), a method for forming a plated film by plating, and a method for attaching a metal foil. In order to form a metal layer 22 having excellent electrical conductivity in the surface direction, the method for forming a vapor-deposited film by physical vapor deposition or CVD, or the method for forming a plated film by plating is preferred. In order to form the metal layer 22 with a thin thickness, a metal layer 22 having excellent electrical conductivity in the surface direction even if it is thin, and the metal layer 22 can be easily formed by a dry process, the method for forming a vapor-deposited film by physical vapor deposition or CVD is more preferred, and the method for forming a vapor-deposited film by physical vapor deposition is even more preferred.

[0068] In the step (A1-3), a conductive adhesive paint is applied to the surface of the metal layer 22 opposite to the insulating resin layer 10. The conductive adhesive paint contains, for example, a thermosetting resin 24a, conductive particles 24b, and a solvent. Examples of solvents contained in the conductive adhesive paint include esters (butyl acetate, ethyl acetate, methyl acetate, isopropyl acetate, ethylene glycol monoacetate, etc.), ketones (methyl ethyl ketone, methyl isobutyl ketone, acetone, methyl isobutyl ketone, cyclohexanone, etc.), alcohols (methanol, ethanol, isopropanol, butanol, propylene glycol monomethyl ether, propylene glycol, etc.), toluene, etc. Examples of a method for applying the conductive adhesive coating material include methods using various coaters such as a die coater, gravure coater, roll coater, curtain flow coater, spin coater, bar coater, reverse coater, kiss coater, fountain coater, rod coater, air doctor coater, knife coater, blade coater, cast coater, and screen coater. The solvent is evaporated from the applied conductive adhesive paint to form an anisotropic conductive adhesive layer 24 .

[0069] In the step (A1-4), the release film 40 is laminated on the surface of the anisotropic conductive adhesive layer 24 opposite the metal layer 22 such that the release agent layer 44 is in contact with the anisotropic conductive adhesive layer 24. After laminating the release film 40 onto the anisotropic conductive adhesive layer 24, the laminate consisting of the carrier film 30, the insulating resin layer 10, the metal layer 22, the anisotropic conductive adhesive layer 24 and the release film 40 may be subjected to a pressure treatment to increase the adhesion between the layers. Heating may be performed simultaneously with the pressure treatment.

[0070] The method (A2) is a method comprising the following steps (A2-1) to (A2-4). Step (A2-1): A step of forming an insulating resin layer 10 on one surface of a carrier film 30. Step (A2-2): A step of forming a metal layer 22 on the surface of the insulating resin layer 10 opposite to the carrier film 30 to obtain a laminate I. Step (A2-3): A step of forming an anisotropic conductive adhesive layer 24 on one surface of a release film 40 to obtain a laminate II. Step (A2-4): A step of bonding the laminate I and the laminate II together so that the metal layer 22 of the laminate I and the anisotropic conductive adhesive layer 24 of the laminate II are in contact with each other.

[0071] Step (A2-1) and step (A2-2) are the same as step (A1-1) and step (A1-2) in the method (A1).

[0072] In step (A2-3), a conductive adhesive paint is applied to the surface of the release film 40 on which the release agent layer 44 is provided. The solvent is evaporated from the applied conductive adhesive paint to form an anisotropic conductive adhesive layer 24. The conductive adhesive paint and the application method are the same as those in step (A1-3) in the method (A1).

[0073] In the bonding of the laminate I and the laminate II in the step (A2-4), a pressure treatment may be performed to enhance the adhesion between the laminate I and the laminate II. The pressure conditions are the same as those in the pressure treatment in the step (A1-4). Heating may also be performed in the step (A2-4) as in the step (A1-4).

[0074] The method (B1) is similar to the method (A1) except that an isotropic conductive adhesive layer 26 is formed instead of the anisotropic conductive adhesive layer 24. The method (B2) is similar to the method (A2) except that an isotropic conductive adhesive layer 26 is formed instead of the anisotropic conductive adhesive layer 24.

[0075] (Action and effect) In the electromagnetic shielding film 1 described above, the conductive particles contained in the electromagnetic shielding layer have a 10% compressive strength of 40 MPa or less, so that the conductive particles 24b are easily deformed during thermocompression bonding of the printed wiring board with the insulating film and the electromagnetic shielding film 1. Therefore, sufficient adhesion between the electromagnetic shielding film 1 and the printed wiring board with the insulating film can be ensured even if the press pressure and press temperature of the thermocompression bonding are low. As a result, defects such as breakage and deformation of the insulating resin layer, the electromagnetic shielding layer, and the printed wiring board can be prevented. In addition, the press time during thermocompression bonding can be short, so that the workability is also excellent. In addition, it is easy to increase the content of the conductive particles and improve the electromagnetic shielding properties and electrical connectivity.

[0076] (Other embodiments) The electromagnetic wave shielding film of this embodiment has an insulating resin layer and an electromagnetic wave shielding layer adjacent to the insulating resin layer, the electromagnetic wave shielding layer contains conductive particles, and the conductive particles have a 10% compressive strength of 40 MPa or less, and is not limited to the first and second embodiments shown in the figures. For example, if the insulating resin layer 10 has sufficient flexibility and strength, the carrier film 30 may be omitted. The electromagnetic wave shielding layer does not necessarily have to include a metal layer. If the adhesive strength of the surface of the conductive adhesive layer is low, the release film 40 may be omitted. The carrier film 30 does not need to have the release agent layer 34 if the carrier film body 32 has sufficient releasability or is a film having self-adhesive properties. The carrier film 30 may have an adhesive layer instead of the release agent layer 34 . The release film 40 does not need to have the release agent layer 44 if the release film body 42 has sufficient releasability or is a film having self-adhesive properties. The release film 40 may have an adhesive layer instead of the release agent layer 44 .

[0077] <Printed wiring board with electromagnetic shielding film> A second aspect of the present invention is a printed wiring board with an electromagnetic wave shielding film, comprising: a printed wiring board having a printed circuit provided on at least one side of a substrate; an insulating film adjacent to the surface of the printed wiring board on which the printed circuit is provided; and an electromagnetic wave shielding film of the first aspect of the present invention adjacent to the side of the insulating film opposite the printed wiring board, with an electromagnetic wave shielding layer in contact with the insulating film.

[0078] FIG. 3 is a cross-sectional view showing one embodiment of a printed wiring board with an electromagnetic shielding film of this aspect. The printed wiring board 2 with an electromagnetic wave shielding film includes a flexible printed wiring board 50, an insulating film 60, and the electromagnetic wave shielding film 1 of the first embodiment. The flexible printed wiring board 50 has a printed circuit 54 provided on at least one surface of a base film 52 . The insulating film 60 is provided on the surface of the flexible printed wiring board 50 on which the printed circuit 54 is provided. The anisotropic conductive adhesive layer 24 of the electromagnetic wave shielding film 1 is adhered to and cured on the surface of the insulating film 60. In addition, the anisotropic conductive adhesive layer 24 is electrically connected to the printed circuit 54 through a through hole (not shown) formed in the insulating film 60. In the printed wiring board 2 with the electromagnetic wave shielding film, the carrier film and the release film have been peeled off from the electromagnetic wave shielding film 1.

[0079] In the vicinity of the printed circuit 54 (signal circuit, ground circuit, ground layer, etc.) excluding the portion with the through hole, the metal layer 22 of the electromagnetic wave shielding film 1 is arranged facing and spaced apart via the insulating film 60 and the anisotropic conductive adhesive layer 24.

[0080] (Flexible Printed Circuit Board) The flexible printed wiring board 50 is formed by processing the copper foil of a copper-clad laminate into a desired pattern by a known etching method to form a printed circuit 54. Examples of copper-clad laminates include those in which copper foil is attached to one or both sides of a base film 52 via an adhesive layer (not shown); and those in which a resin solution or the like that forms a base film 52 is cast onto the surface of the copper foil. Examples of materials for the adhesive layer include epoxy resin, polyester, polyimide, polyamideimide, polyamide, phenol resin, urethane resin, acrylic resin, and melamine resin. The thickness of the adhesive layer is preferably 0.5 μm or more and 30 μm or less.

[0081] The base film 52 is preferably a heat-resistant film, and more preferably a polyimide film, a polyetherimide film, a polyphenylene sulfide film, an aromatic polyether ketone film, or a liquid crystal polymer film. The surface resistance of the base film 52 is set to 1×10 6 The surface resistance of the base film 52 is preferably 1×10 19 Ω / □ or less is preferable. The thickness of the base film 52 is preferably 5 μm or more and 200 μm or less, and from the viewpoint of flexibility, is more preferably 6 μm or more and 50 μm or less, and more preferably 10 μm or more and 25 μm or less.

[0082] Examples of the copper foil constituting the printed circuit 54 include rolled copper foil and electrolytic copper foil, and from the viewpoint of flexibility, rolled copper foil is preferred. The printed circuit 54 is used as a signal circuit, a ground circuit, a ground layer, etc. The thickness of the copper foil is preferably 1 μm or more and 50 μm or less. The ends (terminals) of the printed circuit 54 in the length direction are exposed and not covered by the insulating film 60 or the electromagnetic shielding film 1 for soldering, connector connection, component mounting, and the like.

[0083] (Insulating film) The insulating film 60 (coverlay film) is an insulating film body (not shown) having an adhesive layer (not shown) formed on one side thereof by applying an adhesive, attaching an adhesive sheet, or the like. The surface resistance of the insulating film itself is 1×10 6 Ω / □ or more is preferable. From a practical standpoint, the surface resistance of the insulating film body should be less than 1×10 19 Ω / □ or less is preferable. The insulating film body is preferably a heat-resistant film, such as a polyimide film, a polyetherimide film, a polyphenylene sulfide film, an aromatic polyether ketone film, or a liquid crystal polymer film. The thickness of the insulating film body is preferably 1 μm or more and 100 μm or less from the viewpoint of flexibility. Examples of materials for the adhesive layer include epoxy resin, polyester, polyimide, polyamideimide, polyamide, phenol resin, urethane resin, acrylic resin, melamine resin, polystyrene, polyolefin, etc. The epoxy resin may contain a rubber component (nitrile rubber, acrylic rubber, etc.) for imparting flexibility. The thickness of the adhesive layer is preferably from 1 μm to 100 μm, and more preferably from 1.5 μm to 60 μm.

[0084] There is no particular limitation on the shape of the opening of the through hole formed in the insulating film 60. Examples of the shape of the opening of the through hole include a circle, an ellipse, and a rectangle.

[0085] (Action and effect) In the printed wiring board 2 with an electromagnetic wave shielding film described above, the conductive particles 24b contained in the electromagnetic wave shielding layer 20 of the electromagnetic wave shielding film 1 have a 10% compressive strength of 40 MPa or less, so that the conductive particles 24b are easily deformed during thermocompression bonding of the printed wiring board with an insulating film and the electromagnetic wave shielding film 1. Therefore, sufficient adhesion and electrical connectivity can be ensured even under gentle pressing conditions, and defects such as breakage and deformation of the insulating resin layer 10, the electromagnetic wave shielding layer 20, and the printed wiring board can be prevented during thermocompression bonding. In addition, thermocompression bonding can be performed in a short time, so workability is also excellent.

[0086] (Other embodiments) The printed wiring board with electromagnetic shielding film of this embodiment need only have a printed wiring board having a printed circuit on at least one side of a substrate, an insulating film adjacent to the side of the printed wiring board on which the printed circuit is provided, and an electromagnetic shielding film of the first embodiment of the present invention adjacent to the side of the insulating film opposite the printed wiring board, with a conductive adhesive layer in contact with the insulating film, and is not limited to the embodiment shown in the figures. For example, the flexible printed wiring board 50 may have a ground layer on the back surface side. Alternatively, the flexible printed wiring board 50 may have printed circuits 54 on both sides, and an insulating film 60 and an electromagnetic wave shielding film 1 attached to both sides. Instead of the flexible printed wiring board 50, a rigid printed circuit board that has no flexibility may be used. The electromagnetic wave shielding film 1 of the first embodiment may be replaced by the electromagnetic wave shielding film 1 of the second embodiment.

[0087] <Method of manufacturing a printed wiring board with an electromagnetic wave shielding film> A third aspect of the present invention is a method for producing a printed wiring board with an electromagnetic wave shielding film, comprising stacking a printed wiring board having a printed circuit provided on at least one side of a substrate and an insulating film adjacent to the side of the printed wiring board on which the printed circuit is provided, and an electromagnetic wave shielding film of the first aspect of the present invention, and thermocompression bonding the insulating film and the electromagnetic wave shielding layer in contact with each other.

[0088] The printed wiring board 2 with an electromagnetic wave shielding film can be produced, for example, by a method including the following steps (a) to (e) (see FIG. 4). Step (a): A step of providing an insulating film 60 having a through hole 62 formed in a position corresponding to the printed circuit 54 on the surface of the flexible printed wiring board 50 on which the printed circuit 54 is provided, thereby obtaining a printed wiring board 3 with an insulating film. Step (b): After step (a), a step of temporarily fixing the printed wiring board 3 with the insulating film and the electromagnetic wave shielding film 1 from which the release film 40 has been peeled off, stacking them so that the anisotropic conductive adhesive layer 24 is in contact with the surface of the insulating film 60. Step (c): After step (b), a step of thermocompression bonding the temporarily fixed printed wiring board 3 with the insulating film and the electromagnetic shielding film 1 from which the release film 40 has been peeled off. Step (d): After step (c), a step of peeling off the carrier film 30 when the carrier film 30 is no longer needed. Step (e): If necessary, a step of fully curing the anisotropic conductive adhesive layer 24 after step (d). Each step will be described in detail below with reference to FIG.

[0089] Process (a): Step (a) is a step of laminating an insulating film 60 onto a flexible printed wiring board 50 to obtain a printed wiring board 3 with an insulating film. Specifically, first, an insulating film 60 having through holes 62 formed in positions corresponding to the printed circuits 54 is laid on the flexible printed wiring board 50. Next, an adhesive layer (not shown) of the insulating film 60 is adhered to the surface of the flexible printed wiring board 50, and the adhesive layer is cured to obtain the printed wiring board 3 with the insulating film. The adhesive layer of the insulating film 60 may be temporarily adhered to the surface of the flexible printed wiring board 50, and the adhesive layer may be fully cured in step (d). The adhesive layer is bonded and cured by, for example, thermocompression bonding using a press (not shown) or the like.

[0090] Process (b): Step (b) is a step of thermocompression bonding the electromagnetic wave shielding film 1 to the printed wiring board 3 with an insulating film under mild conditions. Specifically, the electromagnetic shielding film 1 from which the release film 40 has been peeled off is placed on the printed wiring board 3 with the insulating film, and then thermocompression bonded under mild conditions. This makes it possible to temporarily fix the position of the electromagnetic shielding film 1 relative to the printed wiring board 3 with the insulating film. Step (b) eliminates the need for alignment near the high-temperature press used in step (c), eliminating dangerous work.

[0091] The electromagnetic wave shielding film 1 is temporarily fixed by, for example, thermocompression bonding using a press machine (not shown) or the like. The pressing time for thermocompression bonding is preferably 5 seconds to 2 minutes, more preferably 5 seconds to 30 seconds. If the thermocompression bonding time is equal to or more than the lower limit of the above range, the anisotropic conductive adhesive layer 24 can be easily adhered to the surface of the insulating film 60. If the thermocompression bonding time is equal to or less than the upper limit of the above range, the manufacturing time for the printed wiring board 2 with the electromagnetic shielding film can be shortened.

[0092] The pressing temperature for thermocompression bonding (the temperature of the hot platen of the press) is preferably 50°C or higher and 150°C or lower, and more preferably 60°C or higher and 80°C or lower. If the thermocompression bonding temperature is equal to or higher than the lower limit of the above range, the anisotropic conductive adhesive layer 24 can be easily adhered to the surface of the insulating film 60. In addition, the time required for thermocompression bonding can be shortened. If the thermocompression bonding temperature is equal to or lower than the upper limit of the above range, the danger of the work can be reduced.

[0093] The pressure of the thermocompression bonding is more preferably 0.01 MPa or more and 1 MPa or less. If the pressure of the thermocompression bonding is equal to or more than the lower limit of the above range, the anisotropic conductive adhesive layer 24 is adhered to the surface of the insulating film 60. In addition, the time for thermocompression bonding can be shortened. If the pressure of the thermocompression bonding is equal to or less than the upper limit of the above range, the danger of the work can be reduced.

[0094] Process (c): Step (c) is a step of thermocompression bonding the electromagnetic wave shielding film 1 to the printed wiring board 3 with the insulating film. Specifically, the temporarily fixed printed wiring board 3 with the insulating film and the electromagnetic wave shielding film 1 are thermocompression bonded together. As a result, the anisotropic conductive adhesive layer 24 is bonded to the surface of the insulating film 60, and the anisotropic conductive adhesive layer 24 is pressed into the through hole 62, filling the through hole 62 and electrically connecting to the printed circuit 54. As a result, the printed wiring board 2 with the electromagnetic wave shielding film is obtained.

[0095] The anisotropic conductive adhesive layer 24 is adhered and cured by, for example, thermocompression bonding using a press (not shown) or the like. The pressing time for thermocompression bonding is preferably 20 seconds to 60 minutes, more preferably 30 seconds to 30 minutes. If the thermocompression bonding time is equal to or greater than the lower limit of the above range, the anisotropic conductive adhesive layer 24 can be easily bonded to the surface of the insulating film 60. If the thermocompression bonding time is equal to or less than the upper limit of the above range, the manufacturing time for the printed wiring board 2 with the electromagnetic shielding film can be shortened.

[0096] The pressing temperature for thermocompression bonding (the temperature of the hot platen of the press) is preferably 140°C or higher and 200°C or lower, and more preferably 170°C or higher and 190°C or lower. If the thermocompression bonding temperature is equal to or higher than the lower limit of the above range, the anisotropic conductive adhesive layer 24 can be easily bonded to the surface of the insulating film 60. In addition, the time for thermocompression bonding can be shortened. If the thermocompression bonding temperature is equal to or lower than the upper limit of the above range, deterioration of the electromagnetic wave shielding film 1, the flexible printed wiring board 50, etc. can be easily suppressed.

[0097] The pressure of the thermocompression bonding is preferably 0.5 MPa or more and 20 MPa or less, and more preferably 1 MPa or more and 16 MPa or less. If the pressure of the thermocompression bonding is equal to or more than the lower limit of the above range, the anisotropic conductive adhesive layer 24 is adhered to the surface of the insulating film 60. In addition, the time for thermocompression bonding can be shortened. If the pressure of the thermocompression bonding is equal to or less than the upper limit of the above range, damage to the electromagnetic wave shielding film 1, the flexible printed wiring board 50, etc. can be suppressed.

[0098] Process (d): Step (d) is a step of peeling off the carrier film 30. Specifically, when the carrier film is no longer needed, the carrier film 30 is peeled off from the insulating resin layer 10 .

[0099] Process (e): Step (e) is a step of completely curing the anisotropic conductive adhesive layer 24. When the time for thermocompression bonding in step (c) is a short time of 20 seconds or more and 10 minutes or less, it is preferable to carry out main curing of the anisotropic conductive adhesive layer 24 between steps (c) and (d) or after step (d). The anisotropic conductive adhesive layer 24 is fully cured by using a heating device such as an oven. The heating time is from 15 minutes to 120 minutes, and more preferably from 30 minutes to 60 minutes. When the heating time is equal to or more than the lower limit of the above range, the anisotropic conductive adhesive layer 24 can be sufficiently cured. When the heating time is equal to or less than the upper limit of the above range, the manufacturing time of the printed wiring board 2 with the electromagnetic shielding film can be shortened. The heating temperature (ambient temperature in the oven) is preferably 120° C. or higher and 180° C. or lower, and more preferably 120° C. or higher and 160° C. or lower. When the heating temperature is equal to or higher than the lower limit of the above range, the heating time can be shortened. When the heating temperature is equal to or lower than the upper limit of the above range, deterioration of the electromagnetic wave shielding film 1, the flexible printed wiring board 50, and the like can be suppressed.

[0100] (Action and effect) In the above-described method for producing a printed wiring board 2 with an electromagnetic wave shielding film, the conductive particles 24b contained in the electromagnetic wave shielding layer 20 of the electromagnetic wave shielding film 1 have a 10% compressive strength of 40 MPa or less, so that the conductive particles 24b are easily deformed during thermocompression bonding of the printed wiring board with an insulating film and the electromagnetic wave shielding film 1. Therefore, sufficient adhesion and electrical connectivity can be ensured even under gentle pressing conditions, and defects such as breakage and deformation of the insulating resin layer 10, the electromagnetic wave shielding layer 20, and the printed wiring board can be prevented during thermocompression bonding. In addition, since thermocompression bonding can be performed in a short time, the method is also easy to work with.

[0101] (Other embodiments) The method for manufacturing a printed wiring board with an electromagnetic wave shielding film of this embodiment may be a method in which a printed wiring board with an insulating film and an electromagnetic wave shielding film of the first embodiment of the present invention (however, if there is a release film adjacent to the electromagnetic wave shielding layer, the release film is peeled off) are layered together so that the insulating film and the electromagnetic wave shielding layer are in contact with each other, and are thermocompression bonded together, and is not limited to the above-mentioned embodiment. If precise alignment is not required, step (b) may be omitted. In the step (c), if the thermocompression time is long enough to harden the anisotropic conductive adhesive layer 24, the step (e) can be omitted. EXAMPLES

[0102] The present invention will be described in more detail below with reference to examples and comparative examples, but the present invention is not limited to the following examples.

[0103] (Specific gravity of conductive particles) The specific gravity of the conductive particles was measured at a temperature of 23° C. in accordance with Method A of JIS K7112:1999.

[0104] (10% compressive strength of conductive particles) The 10% compression strength of the conductive particles was determined from the results of measurement using a microcompression tester (MCT-510, manufactured by Shimadzu Corporation) and the above formula (α).

[0105] (Average particle size of conductive particles) The average particle diameter of the conductive particles was calculated by randomly selecting 30 particles from the microscopic images of the particles, measuring the minimum and maximum diameters of each particle, determining the median of the minimum and maximum diameters as the particle diameter of one particle, and then taking the arithmetic mean of the measured particle diameters of the 30 particles.

[0106] (Thickness of metal layer, conductive adhesive layer) The thickness of the metal layer was determined by measuring the thickness at five randomly selected locations using an eddy current thickness gauge and averaging the results. The thickness of the conductive adhesive layer was determined by measuring the thickness at five randomly selected locations using a digital length measuring machine (Mitutoyo Corporation, Litematic VL-50-B) and averaging the results.

[0107] (Adhesion test) A 25 μm thick polyimide film and an electromagnetic wave shielding film were layered with the conductive adhesive layer and the polyimide film in contact with each other, and then thermocompression-bonded using a hot press device at a press temperature of 180°C, a press pressure of 13 MPa, and a press time of 300 seconds. After peeling off the carrier film, the polyimide film with the thermocompression-bonded electromagnetic wave shielding film was heated at a temperature of 150°C for 1 hour using a high-temperature incubator to fully cure the anisotropic conductive adhesive layer, thereby obtaining a flexible printed wiring board (test specimen) with an electromagnetic wave shielding film. Using a tensile tester (Shimadzu Corporation Autograph), the polyimide film in the test specimen was peeled off at 180° from the test specimen to measure the peel force, and the adhesion was evaluated according to the following criteria. The peel force was measured and adhesion was evaluated in the same manner when the conditions for thermocompression bonding were press temperature: 180°C, press pressure: 5 MPa, and press time: 120 seconds, and when the conditions for press temperature: 170°C, press pressure: 5 MPa, and press time: 90 seconds. <Evaluation criteria> ◎: Peel strength is 6N / cm or more. ○: Peel strength is 3N / cm or more and less than 6N / cm. ×: Peel strength is less than 3 N / cm.

[0108] (Minimum connection diameter) A flexible printed wiring board 100 with an insulating film for connectivity evaluation (hereinafter, referred to as "evaluation wiring board 100") shown in Fig. 5(A) and Fig. 5(B) was prepared. The evaluation wiring board 100 is formed by laminating a base film (polyimide film) 152 having a thickness of 25 µm, a printed circuit 154 formed by etching a copper foil having a thickness of 12.5 µm, an adhesive layer 156 having a thickness of 25 µm, and an insulating film (polyimide film) 160 having a thickness of 12.5 µm in this order. In the evaluation wiring board 100, two rectangular printed circuits 154 of 20 mm x 3 mm are placed in parallel with an interval of 3 mm. In the insulating film 160 and the adhesive layer 156, one connection test through hole 162 and one resistance measurement through hole 164 having a diameter of 2 mm are formed at positions corresponding to both ends of each printed circuit 154. The distance between the centers of the connection test through holes 162 and the resistance measurement through holes 164 was 15 mm, the distance between the centers of the connection test through holes 162 was 6 mm, and the distance between the centers of the resistance measurement through holes 164 was 6 mm. In addition, the positions of the printed circuit 154 corresponding to the connection test through holes 162 and the resistance measurement through holes 164 were surface treated with a nickel layer having a thickness of 0.5 μm and a gold layer having a thickness of 0.05 μm. Ten evaluation wiring boards 100 were prepared with connection test through holes 162 having diameters ranging from 0.1 mm to 1.0 mm in increments of 0.1 mm.

[0109] As shown in Fig. 6(A) and Fig. 6(B), the electromagnetic shielding film (shielding film 201) of each example and each evaluation wiring board 100 were stacked with the conductive adhesive layer (conductive adhesive layer 224) and the insulating film 160 facing each other so that the connection test through hole 162 was covered and the resistance measurement through hole 164 was not covered, and they were thermocompression-bonded using a hot press device at a press temperature of 180°C, a press pressure of 5 MPa, and a press time of 120 seconds. After peeling off the carrier film, the evaluation wiring board 100 with the thermocompression-bonded shielding film 201 was heated at a temperature of 150°C for 1 hour using a high-temperature incubator to fully cure the conductive adhesive layer 224 on the insulating resin layer (insulating resin layer 210), thereby obtaining a flexible printed wiring board (test specimen) with an electromagnetic shielding film. A tester was placed against the resistance measurement through hole 164 of each test specimen to measure the resistance value of wiring-electromagnetic wave shielding layer-wiring, and among the test specimens with a resistance value of 1 Ω or less, the one with the smallest diameter of the connection test through hole 162 was determined as the minimum connection diameter.

[0110] Example 1 A coating material for forming an insulating resin layer was prepared by dissolving 100 parts by mass of bisphenol A type epoxy resin (manufactured by Mitsubishi Chemical Corporation, jER (registered trademark) 1001), 2 parts by mass of 2-methyl-4-ethylimidazole, and 4 parts by mass of carbon black in 300 parts by mass of a solvent (methyl ethyl ketone). As a carrier film, a PET film (manufactured by Toyobo Co., Ltd., CN200, thickness: 50 μm) was prepared. A thermosetting conductive adhesive paint was prepared by dissolving or dispersing 97 parts by mass of a thermosetting adhesive (a mixture of 100 parts by mass of a urethane resin (Byron UR-3500, manufactured by Toyobo Co., Ltd.) and 5.3 parts by mass of a curing agent (jER 1031S, manufactured by Mitsubishi Chemical Corporation)) and 3 parts by mass of the conductive particles (resin particles with conductive film) shown in Table 1 in 100 parts by mass of a solvent (a mixture of 100 parts by mass of methyl ethyl ketone and 100 parts by mass of toluene).

[0111] The paint for forming an insulating resin layer was applied to the surface of the release agent layer of the carrier film, heated at 100°C for 2 minutes, the paint was dried, and then heated in a high-temperature incubator at a temperature of 120°C for 48 hours to fully harden the paint, forming an insulating resin layer (thickness: 10 μm). Copper was physically deposited on the surface of the insulating resin layer by electron beam deposition to form a metal layer (deposited film, thickness: 0.5 μm). A thermosetting conductive adhesive paint was applied to the surface of the metal layer using a die coater, and the solvent was volatilized to bring it to the B-stage, forming an anisotropic conductive adhesive layer (thickness: 4 μm) and obtaining an electromagnetic wave shielding film. The evaluation results of adhesion and minimum connection diameter are shown in Table 1.

[0112] (Examples 2 to 14) An electromagnetic wave shielding film was produced in the same manner as in Example 1, except that the type and content of the conductive particles used and the thickness of the conductive adhesive layer were changed as shown in Table 1, and the adhesion and the minimum connection diameter were evaluated. The results are shown in Table 1.

[0113] (Comparative Examples 1 to 3) An electromagnetic wave shielding film was produced in the same manner as in Example 1, except that copper particles were used as the conductive particles and the content of the conductive particles and the thickness of the conductive adhesive layer were changed as shown in Table 1, and the adhesion and the minimum connection diameter were evaluated. The results are shown in Table 1.

[0114] [Table 1]

[0115] In addition, the "mass ratio C / S" in Table 1 means the mass ratio of the resin particle (core) to the conductive film (shell) in the resin particle with a conductive film. "PMMA" means polymethyl methacrylate. [Industrial Applicability]

[0116] The electromagnetic wave shielding film of the present invention is useful as an electromagnetic wave shielding member in flexible printed wiring boards for electronic devices such as smartphones, mobile phones, optical modules, digital cameras, game consoles, notebook computers, and medical instruments. [Explanation of symbols]

[0117] 1 Electromagnetic wave shielding film, 2. Printed wiring board with electromagnetic shielding film, 3 Printed wiring board with insulating film, 10 insulating resin layer, 22 metal layer, 20 Electromagnetic shielding layer, 24 anisotropic conductive adhesive layer, 24a thermosetting resin, 24b conductive particles, 26 Isotropic conductive adhesive layer, 26a thermosetting resin, 26b conductive particles, 30 Career Films, 32 Carrier film body, 34 release agent layer, 40 Release film, 42 Release film body, 44 release agent layer, 50 Flexible printed wiring board, 52 Base film, 54 Printed Circuits, 60 Insulating film, 62 through holes.

Claims

1. An insulating resin layer and an electromagnetic wave shielding layer adjacent to the insulating resin layer, the electromagnetic wave shielding layer contains conductive particles, the conductive particles are resin particles having a conductive film formed on the surface of the resin particles, the resin particles contain at least one resin selected from the group consisting of an acrylic resin and a urethane resin, The conductive particles have a 10% compressive strength of 0.25 MPa or more and 40 MPa or less.

2. 2 . The electromagnetic shielding film according to claim 1 , wherein the ratio of the mass of the conductive film to the total mass of the conductive film-attached resin particles is 5 mass % or more and 50 mass % or less.

3. 3. The electromagnetic wave shielding film according to claim 1, wherein the specific gravity of the conductive film is 2.50 or more and 22.0 or less.

4. 4. The electromagnetic wave shielding film according to claim 1, wherein the conductive film contains at least one metal selected from the group consisting of gold, silver, and copper.

5. The electromagnetic wave shielding film according to any one of claims 1 to 4, wherein the conductive film contains two or more different metals.

6. The electromagnetic wave shielding film according to claim 1 , wherein the conductive film comprises a sputtered film.

7. The electromagnetic wave shielding film according to claim 1 , wherein the conductive film comprises a plating film.

8. 8. The electromagnetic wave shielding film according to claim 1, wherein the conductive particles have a specific gravity of 1.00 or more and 3.00 or less.

9. The electromagnetic wave shielding film according to any one of claims 1 to 8, wherein the conductive particles have an average particle size of 0.5 µm or more and 20 µm or less.

10. the electromagnetic wave shielding layer has a metal layer adjacent to the insulating resin layer and a conductive adhesive layer adjacent to the metal layer on the opposite side to the insulating resin layer, The electromagnetic wave shielding film according to any one of claims 1 to 9, wherein the conductive adhesive layer contains the conductive particles.

11. the conductive adhesive layer contains either one or both of a thermosetting resin and a thermoplastic resin, and the conductive particles; The electromagnetic wave shielding film according to claim 10 , wherein the content of the conductive particles in the conductive adhesive layer is 0.2% by mass or more and 60% by mass or less with respect to the total mass of the conductive adhesive layer.

12. The electromagnetic wave shielding film according to any one of claims 1 to 11, wherein the insulating resin layer has a thickness of 1.0 µm or more and 20 µm or less.

13. A printed wiring board having a printed circuit provided on at least one surface of a substrate; an insulating film adjacent to a surface of the printed wiring board on which the printed circuit is provided; The electromagnetic wave shielding film according to any one of claims 1 to 12, which is adjacent to the insulating film on a side opposite to the printed wiring board, and the electromagnetic wave shielding layer is in contact with the insulating film; A printed wiring board with an electromagnetic wave shielding film.

14. a printed wiring board having a printed circuit provided on at least one surface of a substrate and an insulating film provided with an insulating film adjacent to the surface of the printed wiring board on which the printed circuit is provided; The electromagnetic wave shielding film according to any one of claims 1 to 12, The insulating film and the electromagnetic wave shielding layer are overlapped so as to be in contact with each other, and then thermocompression bonded to each other.

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