JP5866266B2 - Electromagnetic wave shielding film, method for producing electromagnetic wave shielding film, and method for producing flexible printed wiring board - Google Patents

Description

The present invention, electromagnetic wave shielding film and production method thereof, and relates to the production how the flexible printed wiring board using an electromagnetic wave shielding film.

Electromagnetic wave noise generated from a flexible printed wiring board, electronic components, or the like constituting the electronic device affects other electric circuits and electronic components, and causes the electronic device to malfunction.
Conventionally, as a method of manufacturing a flexible printed wiring board having an electromagnetic wave shielding function, there is a method of adhering an electromagnetic wave shielding film to a flexible printed wiring board (see, for example, Patent Document 1 and Patent Document 2).

  Patent Document 1 describes a method for manufacturing a shield film in which a cover film is formed on one surface of a separate film, and a shield layer composed of a metal thin film layer and an adhesive layer is formed on the surface of the cover film. Patent Document 1 discloses a flexible printed wiring in which a shield film is placed on a base film so that the shield layer is in contact, the shield film is bonded to the base film of the flexible printed wiring board, and the separate film is peeled off. A plate manufacturing method has been proposed.

  In Patent Document 2, a shield film having a shield layer on one side of a cover film and a reinforcing film that can be easily peeled on the other side is attached to a base film of a flexible printed wiring board, and then the reinforcing film is peeled off. A flexible printed wiring board is described.

  However, when the conventional electromagnetic wave shielding film is bonded to the flexible printed wiring board, the electromagnetic wave shielding function is provided, and the ground circuit provided on the flexible printed wiring board and the electromagnetic wave shielding film are provided. It was necessary to electrically connect the shield layer through the insulating layer disposed between them. For this reason, when the conventional electromagnetic wave shielding film is bonded to the flexible printed wiring board, a step of providing a through hole in the insulating layer and a step of filling the through hole with a conductive material are performed, so that the ground circuit and the shield are formed. It was indispensable to electrically connect the layers, and it took time and effort.

In order to solve this problem, a coverlay film including a shield layer having a thin portion at a predetermined pitch has been proposed (see, for example, Patent Document 3).
Patent Document 3 includes a base film having a concavo-convex surface and a non-concave surface excluding the concavo-convex surface, and a deposited film made of a conductive material formed on the surface of the base film on the side where the concavo-convex surface is formed. A coverlay film having been proposed.

  In the electromagnetic wave shielding film in which the shield layer has thin portions at a predetermined pitch, a portion having a high surface resistance and a portion having a low surface resistance are formed on the shield layer. Therefore, electromagnetic wave noise flows as a high-frequency current through a portion of the shield layer having a low surface resistance, and heat is lost and attenuated in the portion of the high surface resistance.

  That is, in the electromagnetic wave shielding film provided with the shield layer having a thin portion at a predetermined pitch, an electromagnetic wave shielding function can be obtained without connecting the shield layer to the ground circuit of the flexible printed wiring board. Therefore, such an electromagnetic wave shielding film has a process of providing a through hole in an insulating layer and a conductive material in the through hole in order to electrically connect a ground circuit and a shield layer when bonding to a flexible printed wiring board. It is not necessary to carry out the step of filling.

In such an electromagnetic wave shielding film, a shield layer having a thin portion at a predetermined pitch is formed using the manufacturing method shown below.
In other words, before forming the shield layer, a thin portion of the shield layer is formed on the concavo-convex surface by selectively forming the concavo-convex surface in a partial region of the formation surface on which the shield layer is formed. I try to do it. In addition, as a method of forming a concavo-convex surface in a partial region of the formation surface where the shield layer is formed, a roughening treatment, printing, and etching treatment are selectively performed in a partial region on the base film. The method of doing is used.

JP 2004-95566 A JP 2003-298285 A JP 2010-212300 A

  However, in the conventional electromagnetic wave shielding film provided with a shield layer having a thin portion at a predetermined pitch, it is possible to selectively form an uneven surface in a partial region of the formation surface on which the shield layer is formed. It was necessary to perform an extra step, and productivity was insufficient.

The present invention has been made in view of the above circumstances, and it is not necessary to connect the shield layer to the ground circuit of the flexible printed wiring board, and to provide an electromagnetic wave shielding film that can be efficiently manufactured and a method for manufacturing the same. Let it be an issue.
Moreover, the present invention does not require the shield layer of the electromagnetic wave shielding film to be connected to the ground circuit of the flexible printed wiring board, and can be efficiently manufactured, and a flexible printed wiring board obtained by the manufacturing method. It is an issue to provide.

  The electromagnetic wave shielding film of the present invention is formed on a release film, includes insulating particles therein, an insulating resin layer having a convex portion derived from the insulating particles on the surface opposite to the release film, and the insulation It includes a shield layer made of a conductive material formed by physically depositing a metal on a resin layer, and an adhesive layer formed on the shield layer.

In the electromagnetic wave shielding film, the average particle diameter (D) of the insulating particles and the thickness (T) of the region made of only the insulating resin in a plan view of the insulating resin layer satisfy the following formula (1): It may be.
0.5T ≦ D ≦ 2T (1)

Moreover, in said electromagnetic wave shield film, the range of 1-15 micrometers may be sufficient as the average particle diameter of the said insulating particle.
In the electromagnetic wave shielding film, the insulating particles may be transparent.

In the electromagnetic wave shielding film, at least one other insulating resin layer may be provided between the release film and the insulating resin layer.
Moreover, in said electromagnetic wave shield film, the insulating resin contained in the said insulating resin layer may have a higher hardness than the insulating resin contained in the said other insulating resin layer.
Moreover, in said electromagnetic wave shield film, the other insulating resin layer which touches the said release film may contain a transparent particle.

  In the method for producing an electromagnetic wave shielding film of the present invention, a coating solution containing an insulating resin and insulating particles is applied onto a release film, the insulating particles are contained inside, and the insulation is provided on the surface opposite to the release film. A coating step of forming an insulating resin layer having convex portions derived from particles, a vapor deposition step of forming a shield layer made of a conductive material by physically depositing a metal on the insulating resin layer, and the shield Forming an adhesive layer on the layer.

  The method for producing a flexible printed wiring board according to the present invention is the flexible printed wiring board main body in which a wiring conductor is formed on an insulating film, wherein the electromagnetic wave shielding film according to any one of the above is used, and the adhesive layer is the flexible printed wiring board. It includes a step of adhering so as to contact the wiring board body and a step of peeling the release film.

  The method for producing a flexible printed wiring board according to the present invention includes the electromagnetic wave shielding film according to any one of the above, on a flexible printed wiring board body in which a wiring conductor is formed on an insulating film, with a coverlay film interposed therebetween. It includes a step of adhering an adhesive layer so as to contact the coverlay film and a step of peeling the release film.

  The flexible printed wiring board of the present invention is obtained by the above manufacturing method.

  The electromagnetic wave shielding film of the present invention is formed on a release film, includes insulating particles therein, an insulating resin layer having a convex portion derived from the insulating particles on the surface opposite to the release film, and the insulation It includes a shield layer made of a conductive material formed by physically depositing a metal on a resin layer, and an adhesive layer formed on the shield layer. Therefore, in the electromagnetic wave shielding film of the present invention, a portion having a high surface resistance and a portion having a low surface resistance are formed in the shield layer due to the difference in the thickness dimension of the shield layer due to the convex portion of the insulating resin layer.

  Therefore, in the electromagnetic wave shielding film of the present invention, electromagnetic noise flows as a high-frequency current through a portion having a low surface resistance of the shield layer, and is lost and attenuated in a portion having a high surface resistance. That is, the electromagnetic wave shielding film of the present invention can provide an electromagnetic wave shielding function without connecting the shield layer to the ground circuit of the flexible printed wiring board.

  In addition, since the insulating resin layer of the electromagnetic wave shielding film of the present invention contains insulating particles inside the release film, a coating solution containing the insulating resin and insulating particles is applied on the release film. By the method, an insulating resin layer having convex portions derived from insulating particles on the surface can be easily and efficiently formed. Then, by physically depositing metal on the insulating resin layer, it is possible to easily form a shield layer having a thickness dimension distribution based on the convex portions of the insulating resin layer.

  Therefore, the electromagnetic wave shielding film of the present invention is manufactured, for example, in comparison with a case where an uneven surface is selectively formed in a partial region of a formation surface on which the shield layer is formed before the shield layer is formed. The process can be simplified and the productivity is excellent.

FIG. 1 is a cross-sectional view showing an example of the electromagnetic wave shielding film of the present invention. FIG. 2 is a cross-sectional view showing another example of the electromagnetic wave shielding film of the present invention. FIG. 3 is a cross-sectional view showing another example of the electromagnetic wave shielding film of the present invention. FIG. 4 is a cross-sectional view for explaining a method of manufacturing the electromagnetic wave shielding film shown in FIG. FIG. 5 is a cross-sectional view showing an example of the flexible printed wiring board of the present invention. FIG. 6 is a cross-sectional view for explaining a method of manufacturing the flexible printed wiring board shown in FIG. FIG. 7 is a sectional view showing another example of the flexible printed wiring board of the present invention. FIG. 8 is a three-dimensional (3D) image of the electromagnetic wave shielding film of Example 1 being manufactured.

<Electromagnetic wave shielding film>
FIG. 1 is a cross-sectional view showing an example of the electromagnetic wave shielding film of the present invention.
The electromagnetic wave shielding film 11 shown in FIG. 1 is obtained by laminating an insulating resin layer 21, a shielding layer 27, and an adhesive layer 30 in this order on a release film 20.
(Release film)
Examples of the release film 20 include a resin film made of polypropylene, polyethylene, polyester, polyimide, polyamide, or the like. Even if a release agent layer made of a silicon film or the like is provided on the surface (the upper surface in FIG. 1) of the release film 20 on the side of the insulating resin layer 21 in order to facilitate peeling from the insulating resin layer 21. Good.

(Insulating resin layer)
The insulating resin layer 21 includes insulating particles 21b inside. As shown in FIG. 1, the insulating resin layer 21 includes an insulating resin 21 a and insulating particles 21 b, and a convex portion derived from the insulating particles 21 b on the surface opposite to the release film 20 (upper surface in FIG. 1). have. An inclined surface 21 c that is inclined with respect to the extending direction of the electromagnetic wave shielding film 11 is formed on the surface of the convex portion of the insulating resin layer 21.
The surface resistance of the insulating resin layer 21 is preferably 1 × 10 ⁶ Ω or more.

The insulating resin layer 21 has an average particle diameter (D) of the insulating particles 21b and a thickness (T) of a region made of only the insulating resin in a plan view of the insulating resin layer 21 satisfying the following formula (1). Is preferred.
0.5T ≦ D ≦ 2T (1)
When the average particle diameter (D) of the insulating particles 21b and the thickness (T) of the region made of only the insulating resin in a plan view of the insulating resin layer 21 satisfy the above formula (1), the release film 20 of the insulating resin layer 21 The surface on the opposite side is formed with a convex portion, which is a region where the insulating particles 21b are arranged in a plan view, and a flat region consisting only of the insulating resin 21a where the insulating particles 21b are not arranged. Become. As a result, a good thickness dimension distribution can be imparted to the shield layer 27 formed on the insulating resin layer 21.

  The thickness (T) of the region made of only the insulating resin in a plan view of the insulating resin layer 21 is preferably in the range of 2 to 15 μm, and the insulating resin layer is one layer like the electromagnetic wave shielding film 11 shown in FIG. When it consists of only, it is more preferable that it is the range of 4-10 micrometers. When the thickness of the insulating resin layer 21 is within the above range, good insulating performance can be obtained, and without reducing the flexibility of the flexible printed wiring board manufactured using the electromagnetic wave shielding film 11 shown in FIG. preferable.

The shape of the insulating particles 21b can be spherical, cubic, rod-like, dendritic or the like, and is not particularly limited. However, the insulating particles 21b are formed by a method of applying a coating solution containing the insulating resin 21a and the insulating particles 21b on the release film 20. When the insulating resin layer 21 is formed, a coating liquid that is easy to apply is obtained, and a coating film in which the insulating particles 21b are uniformly dispersed can be easily formed.
The insulating particles 21b preferably have a uniform particle size with a sharp distribution. The insulating particles 21b may contain minute air.

  The insulating resin layer 21 affects the appearance of the flexible printed wiring board when the flexible printed wiring board is manufactured using the electromagnetic wave shielding film 11 shown in FIG. When the insulating particles 21b of the insulating resin layer 21 are transparent, it is preferable because a flexible printed wiring board having a good appearance with suppressed gloss can be obtained.

  The average particle diameter of the insulating particles 21b is preferably in the range of 1 to 15 μm, and more preferably in the range of 2 to 12 μm. When the average particle size of the insulating particles 21b is 15 μm or less, the coating used when the insulating resin layer 21 is formed on the release film 20 by a method of applying a coating solution containing the insulating resin 21a and the insulating particles 21b. The liquid insulating particles 21b are preferable because they are less likely to settle and have excellent storage stability. Moreover, when the average particle diameter of the insulating particles 21b is 15 μm or less, it is possible to easily form a coating film in which the insulating particles 21b are uniformly dispersed. Further, when the average particle diameter of the insulating particles 21b is 1 μm or more, the difference between the maximum dimension and the minimum dimension of the shield layer 27 can be easily and sufficiently secured, and the shield layer 27 has a better electromagnetic shielding function. It will be a thing.

  As the material of the insulating particles 21b, a material having a specific gravity in the range of 0.8 to 2.5 is used because it is easy to handle when forming a coating liquid containing the insulating resin 21a and the insulating particles 21b. preferable. Examples of the material having such a specific gravity include resins such as polystyrene, acrylic, epoxy, polyimide, liquid crystal polymer, polyamide, polyphenylene sulfide, polyamideimide, polyetherimide, polyethylene naphthalate, polyethylene terephthalate, and phenol.

  As the insulating resin 21a, for example, a thermosetting resin such as an epoxy resin, a phenol resin, an amino resin, an alkyd resin, or a urethane resin, or a photocurable resin such as an acrylate resin can be used.

(Shield layer)
The shield layer 27 is made of a conductive material, and is formed by physically depositing metal. As shown in FIG. 1, the shield layer 27 is formed on the insulating resin layer 21, and an uneven shape based on the protruding portion of the insulating resin layer 21 is formed on the surface.

  In the shield layer 27 shown in FIG. 1, a portion having a high surface resistance and a portion having a low surface resistance are formed due to a difference in thickness due to the convex portion of the insulating resin layer 21. In more detail, in the electromagnetic wave shielding film 11 shown in FIG. 1, it becomes the surface inclined with respect to the extending direction of the electromagnetic wave shielding film 11 among the parts which overlap with the convex part of the insulating resin layer 21 by planar view. The thickness t 1 of the inclined shield layer 27 (shield layer 27 formed on the inclined surface 21 c of the insulating resin layer 21) is the thickness of the flat shield layer 27 parallel to the extending direction of the electromagnetic wave shielding film 11. It is thinner than t2. As a result, the shield layer 27 has a low resistance portion 27a whose surface resistance is low due to its relatively thick thickness, and a high resistance portion 27b whose surface resistance is high because its thickness is thinner than its surroundings. Is formed.

Specifically, the shield layer 27 preferably has a non-uniform thickness in the range of 50 to 400 nm, and more preferably in the range of 80 to 200 nm.
The minimum dimension of the thickness of the shield layer 27 is preferably 50 nm or more in order to obtain the electromagnetic wave shielding film 11 that can reliably obtain the electromagnetic wave shielding function. Further, the minimum dimension of the thickness of the shield layer 27 is preferably 200 nm or less, and more preferably 100 nm or less so that the dimensional difference from the maximum dimension of the shield layer 27 is sufficiently large. .

  Further, the maximum dimension of the thickness of the shield layer 27 is 100 nm or more in order to secure a sufficient dimensional difference from the minimum dimension of the thickness of the shield layer 27 and to ensure the electromagnetic wave shielding function. Preferably there is. Moreover, when the maximum dimension of the thickness of the shield layer 27 is 200 nm or less, the thickness of the electromagnetic wave shielding film 11 can be sufficiently reduced, and the electromagnetic wave shielding film 11 having excellent bending resistance is obtained, which is preferable. .

The shield layer 27 has a non-uniform surface resistance in the range of 0.01 to 10Ω in order to make the electromagnetic wave shielding film 11 capable of reliably obtaining an electromagnetic wave shielding function for reflecting electromagnetic waves. It is preferable that
The maximum value of the surface resistance of the shield layer 27 is preferably 2 to 100 times, and more preferably 3 to 50 times the minimum value of the surface resistance of the shield layer 27. When the maximum value of the surface resistance of the shield layer 27 is 2 to 100 times the minimum value, the shield layer 27 is preferable because the high-frequency current flowing through the low resistance portion 27a is sufficiently lost in the high resistance portion 27b.

  The transmission attenuation characteristic of the shield layer 27 is preferably −10 dB or less, and more preferably −20 dB or less. The transmission attenuation characteristic of the shield layer 27 can be measured using, for example, a coaxial tube type shield effect measurement system (manufactured by Keycom) that measures the shield effect with a plane wave in accordance with ASTM D4935.

The shield layer 27 is made of a conductive material. Examples of the conductive material used for the shield layer 27 include metals and conductive ceramics, and it is preferable to use conductive ceramics from the viewpoint of improving environmental resistance.
Examples of the metal include gold, silver, copper, aluminum, nickel and the like.
Examples of the conductive ceramic include an alloy, an intermetallic compound, a solid solution, and the like including a metal and one or more elements selected from the group consisting of boron, carbon, nitrogen, silicon, phosphorus, and sulfur. Specifically, as the conductive ceramic, nickel nitride, titanium nitride, tantalum nitride, chromium nitride, titanium carbide, silicon carbide, chromium carbide, vanadium carbide, zirconium carbide, molybdenum carbide, tungsten carbide, chromium boride, molybdenum boride , Chromium silicide, zirconium silicide and the like.

(Adhesive layer)
The adhesive layer 30 is for attaching the electromagnetic wave shielding film 11 to a flexible printed wiring board. The adhesive layer 30 shown in FIG. 1 fills in between the uneven shapes formed on the surface of the shield layer 27 of the electromagnetic wave shielding film 11 and also fills in between the wiring conductors formed on the surface of the flexible printed wiring board described later. The flexible printed wiring board and the electromagnetic wave shielding film 11 are bonded together.

  Examples of the material for the adhesive layer 30 include epoxy resin, polyester, polyimide, polyamideimide, polyamide, phenol resin, polyurethane, acrylic resin, melamine resin, polystyrene, and polyolefin. The epoxy resin may contain a rubber component (carboxyl-modified nitrile rubber or the like) for imparting flexibility.

  The thickness of the adhesive layer 30 is preferably 5 μm or more and more preferably 10 μm or more in order to fill the gap between the flexible printed wiring board and the electromagnetic wave shielding film 11 without any gap. Moreover, in order to ensure the flexibility of a flexible printed wiring board, the thickness of the adhesive layer 30 is preferably 40 μm or less, and more preferably 25 μm or less.

<Other examples of electromagnetic wave shielding film>
The electromagnetic wave shielding film of the present invention is not limited to the electromagnetic wave shielding film 11 shown in FIG. For example, the insulating resin layer 21 may be only one layer as shown in FIG. 1, but at least one other insulating resin layer is provided between the release film 20 and the insulating resin layer. Also good.

  FIG. 2 is a cross-sectional view showing another example of the electromagnetic wave shielding film of the present invention. 2 is different from the electromagnetic wave shielding film shown in FIG. 1 only in that an insulating resin layer 23 and another insulating resin layer 22 are provided between the release film 20 and the shield layer 27. Therefore, about the same member as the electromagnetic wave shielding film shown in FIG. 1, the same code | symbol is attached | subjected and description is abbreviate | omitted.

  The electromagnetic wave shielding film 12 shown in FIG. 2 has two insulating resin layers: an insulating resin layer 23 disposed in contact with the shield layer 27 and another insulating resin layer 22 disposed in contact with the release film 20. doing. As shown in FIG. 2, the insulating resin layer 23 is composed of insulating resin 23a and insulating particles 23b, and the other insulating resin layer 22 is composed of insulating resin 22a and insulating particles 22b. The other insulating resin layer 22 may be provided as only one layer as shown in FIG. 2, or may be provided as two or more layers.

  When at least one other insulating resin layer 22 is provided between the release film 20 and the insulating resin layer 23, the thickness (T) of the region made of only the insulating resin in a plan view of the insulating resin layer 23 The total thickness of all other insulating resin layers 22 ("other insulating resin layer 22" in FIG. 2) and the thickness (T) of the region made of only the insulating resin in plan view is in the range of 2 to 15 μm. It is preferable. Moreover, it is preferable that the thickness (T) of the area | region which consists only of insulating resin by planar view of each layer of the insulating resin layer 23 and the other insulating resin layer 22 is the range of 1-10 micrometers.

  As described above, when at least one other insulating resin layer 22 is provided between the release film 20 and the insulating resin layer 23, the insulating resin layer 23 and / or other insulation is provided when the electromagnetic wave shielding film 12 is bent. Even if defects such as cracks occur in the resin layer 22, the layers complement each other. Therefore, when at least one other insulating resin layer 22 is provided between the release film 20 and the insulating resin layer 23, compared to the case where the insulating resin layer 21 shown in FIG. Thus, even if the thickness of each layer is reduced, good insulating performance can be obtained.

Therefore, even if the average particle diameter of the insulating particles 23b included in the insulating resin layer 23 is less than 1 μm, the average particle diameter (D) of the insulating particles 23b and the thickness of the region made of only the insulating resin in the plan view of the insulating resin layer 23 ( T) can satisfy the following formula (1). For example, when the thickness (T) of the insulating resin layer 23 is 1 μm, the average particle diameter of the insulating particles 23b can be 0.5 μm.
0.5T ≦ D ≦ 2T (1)
As a result, even if the average particle diameter of the insulating particles 23b is less than 1 μm, the surface of the insulating resin layer 23 opposite to the release film 20 is a convex portion that is a region where the insulating particles 23b are arranged in plan view. And the insulating particles 23b are not disposed, and a flat region made only of the insulating resin 23a is formed, and a good thickness dimension distribution is imparted to the shield layer 27 formed on the insulating resin layer 23. It will become a thing.

When at least one other insulating resin layer 22 is provided between the release film 20 and the insulating resin layer 23, the average particle diameter of the insulating particles 23b of the insulating resin layer 23 is 0.5 to 12 μm. A range is preferable.
Moreover, as shown in FIG. 2, the convex part derived from the insulating particle 22b is formed in the surface on the opposite side to the release film 20 of the other insulating resin layer 22, but the release film of the insulating resin layer 23 is formed. As long as a convex portion is formed on the surface opposite to the surface 20, the convex portion may not be formed on the surface of the other insulating resin layer 22 opposite to the release film 20. For this reason, the average particle diameter of the insulating particles 22b of the other insulating resin layers 22 can be in the range of 0.1 to 12 μm.

The insulating resin layer 23 and the other insulating resin layer 22 may have the same thickness made of the same material, or may have different materials and / or thicknesses.
For example, it is preferable that the insulating resin layer 23 and the other insulating resin layer 22 are made of the same material because the insulating resin layer 23 and the other insulating resin layer 22 can be continuously and efficiently formed.

  When the insulating resin layer 23 and the other insulating resin layer 22 are made of different materials, the insulating resin 23 a included in the insulating resin layer 23 is more than the insulating resin 22 a included in the other insulating resin layer 22. It is preferably made of a material having high hardness. When the hardness of the insulating resin 23a included in the insulating resin layer 23 is higher than the hardness of the insulating resin 22a included in the other insulating resin layer 22, the shield layer is formed by physically depositing a metal on the insulating resin layer 23. When 27 is formed, the material to be the shield layer 27 can be prevented from getting into the insulating resin layer 23. If the material that forms the shield layer 27 penetrates into the insulating resin layer 23, the resistance value of the shield layer 27 increases, and the function as the shield layer 27 may be reduced.

  The hardness of the insulating resin layer 23 and the other insulating resin layer 22 can be relatively measured by examining the relationship between the load and the displacement in a minute area in the phase mode of the scanning probe microscope. Therefore, the hardness of the insulating resin layer 23 and the other insulating resin layer 22 can be compared.

  Further, as shown in FIG. 2, the other insulating resin layer 22 in contact with the release film 20 has an appearance of the flexible printed wiring board when the flexible printed wiring board is manufactured using the electromagnetic wave shielding film 12 shown in FIG. It will affect. When the insulating particles 22b of the other insulating resin layers 22 are transparent, a flexible printed wiring board having a good appearance with suppressed gloss is obtained, which is preferable.

  FIG. 3 is a cross-sectional view showing another example of the electromagnetic wave shielding film of the present invention. 3 is different from the electromagnetic wave shielding film shown in FIG. 1 only in that another insulating resin layer 28 in contact with the release film 20 is provided between the release film 20 and the insulating resin layer 21. is there. For this reason, about the same member as the electromagnetic wave shielding film shown in FIG. 1, the same code | symbol is attached | subjected and description is abbreviate | omitted.

The other insulating resin layer 28 shown in FIG. 3 is a flat layer made of an insulating resin, and unlike the other insulating resin layer 22 shown in FIG. 2, does not include the insulating resin 22a.
Examples of the material used for the other insulating resin layer 28 shown in FIG. 3 include a thermosetting resin, a photocurable resin, and the like, similarly to the material used for the insulating resin included in the insulating resin layer 21. In the electromagnetic wave shielding film 13 shown in FIG. 3, the other insulating resin layer 28 and the insulating resin contained in the insulating resin layer 21 may be the same or different.

  When the insulating resin layer 21 and the other insulating resin layer 28 are made of different materials, the insulating resin 21a included in the insulating resin layer 21 is made of a material having higher hardness than the insulating resin of the other insulating resin layer 28. It is preferable that When the insulating resin 21a included in the insulating resin layer 21 is made of a material having higher hardness than the insulating resins of the other insulating resin layers 28, the shield layer 27 is formed by physically depositing metal. In addition, the material for the shield layer 27 can be prevented from getting into the insulating resin layer 21.

  In the electromagnetic wave shielding film 13 of the present invention shown in FIG. 3, since another insulating resin layer 28 not including the insulating resin 22 a is provided between the release film 20 and the insulating resin layer 21, a flexible print described later is provided. When the electromagnetic wave shielding film is adhered to the wiring board and the release film 20 is peeled off, the insulating resin 21a between the insulating particles 21b included in the insulating resin layer 21 and the surface of the insulating resin layer 21 on the release film 20 side. In addition, it is possible to prevent cracks from occurring. The other insulating resin layer 28 functions as a protective layer that protects the insulating resin layer 21 from external contact after the release film 20 is peeled off.

The thickness of the other insulating resin layer 28 can sufficiently prevent the occurrence of cracks when the release film 20 is peeled off, and has a sufficient function as an insulating layer after the release film 20 is peeled off. Thus, it is preferably 2 μm or more. Further, the thickness of the other insulating resin layer 28 is preferably 10 μm or less in order to ensure the flexibility of the flexible printed wiring board.
Further, in the electromagnetic wave shielding film 13 of the present invention shown in FIG. 3, since the other insulating resin layer 28 does not contain insulating particles, the interface between the insulating particles and the insulating resin, which is a weak mechanical strength, is present. not exist. For this reason, the electromagnetic wave shielding film 13 has superior bending performance compared to the case where another insulating resin layer containing insulating particles is provided instead of the other insulating resin layer 28 not containing insulating particles. doing.

<Method for producing electromagnetic shielding film>
Next, as an example of the method for producing the electromagnetic wave shielding film of the present invention, the method for producing the electromagnetic wave shielding film shown in FIG. 1 will be described as an example.
In order to manufacture the electromagnetic wave shielding film 11 shown in FIG. 1, first, a release film 20 is prepared. Next, a coating liquid containing the insulating resin 21a and the insulating particles 21b is manufactured. The coating liquid contains a solvent as required in addition to the insulating resin 21a and the insulating particles 22b. As the solvent, a solvent that does not dissolve the insulating particles 21b but dissolves the insulating resin 21a is used.

Specifically, for example, the insulating particle 21b is made of a thermosetting resin, the insulating resin 21a is made of a main agent including a resin before curing to be the insulating resin 21a, and a curing agent, and the solvent is used. As above, an alcohol such as isopropyl alcohol and an organic solvent such as toluene can be used singly or in combination.
The ratio between the insulating particles 21b and the insulating resin 21a contained in the coating liquid is determined by the average particle diameter (D) of the insulating particles 21b and the thickness (T) of the region made only of the insulating resin in the plan view of the insulating resin layer 21. It is more preferable to easily satisfy the above formula (1).

  As shown in FIG. 4, the coating solution thus obtained is applied onto a release film 20, and if necessary, one or more curing steps selected from drying, heating, and light irradiation are performed for insulation. The resin is cured. Thereby, the insulating resin layer 21 having a convex portion derived from the insulating particles 21b is formed on the surface opposite to the release film 20 (application step).

  In addition, as shown in FIG. 2, when providing the other insulating resin layer 22 which consists of insulating resin 22a and the insulating particle 22b between the release film 20 and the insulating resin layer 23, the release film shown in FIG. In the same manner as when the insulating resin layer 21 is formed on 20, another insulating resin layer 22 is first formed on the release film 20 shown in FIG. Thereafter, in the same manner as the method for forming the other insulating resin layer 22, the insulating resin layer 23 is formed by applying a coating liquid containing the insulating resin 23 a and the insulating particles 23 b on the other insulating resin layer 22. Good.

  Further, before performing the coating process, a process of providing another insulating resin layer 28 shown in FIG. 3 on the release film 20 may be performed as necessary. Examples of the method of providing the other insulating resin layer 28 include a method of sticking a film made of an insulating resin to be the other insulating resin layer 28 on the release film 20, or an insulating resin layer 28 on the release film 20. And a method of applying a coating solution containing an insulating resin.

Next, a shield layer 27 made of a conductive material and having a thickness dimension distribution based on the convex portion of the insulating resin layer 21 is formed by physically depositing a metal on the insulating resin layer 21 (deposition step). Examples of a method for physically depositing metal on the insulating resin layer 21 include an ion beam deposition method and a sputtering method.
The convex portion of the insulating resin layer 21 has a larger area including the actual convex portion than the projected area when viewed from the upper surface in the direction orthogonal to the surface of the insulating resin layer 21. For this reason, when a metal is physically vapor-deposited on the insulating resin layer 21 with the same vapor deposition amount, the electromagnetic wave shielding film 11 among the vapor-deposited films (shield layers) formed on the convex portions of the insulating resin layer 21 in plan view. Is a flat region in which the deposited film (shield layer 27 formed on the inclined surface 21c of the insulating resin layer 21) is inclined with respect to the extending direction of the electromagnetic wave shielding film 11 and parallel to the extending direction of the electromagnetic wave shielding film 11. It becomes thinner than the vapor-deposited film formed.

Thereafter, the adhesive layer 30 is formed on the shield layer 27. As a method of forming the adhesive layer 30, for example, a method of sticking a film to be the adhesive layer 30 on the shield layer 27, or a paint containing a material to be the adhesive layer 30 on the shield layer 27 is applied. The method etc. are mentioned.
By performing the above process, the electromagnetic wave shielding film 11 shown in FIG. 1 is obtained.

<Flexible printed wiring board>
Next, as an example of the flexible printed wiring board of the present invention, a flexible printed wiring board manufactured using the electromagnetic wave shielding film shown in FIG. 1 will be described as an example. In the present invention, the electromagnetic wave shielding film 12 shown in FIG. 2 or the electromagnetic wave shielding film 13 shown in FIG. 3 may be used instead of the electromagnetic wave shielding film 11 shown in FIG.
FIG. 5 is a cross-sectional view showing an example of the flexible printed wiring board of the present invention. In the flexible printed wiring board 41 shown in FIG. 5, the same members as those of the electromagnetic wave shielding film 11 shown in FIG.

A flexible printed wiring board 41 shown in FIG. 5 includes a shield layer 27 disposed on the flexible printed wiring board main body 50 via an adhesive layer 30 and an insulating resin layer 21 disposed on the shield layer 27. .
The adhesive layer 30, the shield layer 27, and the insulating resin layer 21 disposed on the flexible printed wiring board main body 50 are released after the electromagnetic wave shielding film 11 shown in FIG. 1 is stuck on the flexible printed wiring board main body 50. It is formed by peeling the film 20.

  The flexible printed wiring board main body 50 has a wiring conductor 53 formed on one surface (upper surface in FIG. 5) of the insulating film 51, and on the other surface (lower surface in FIG. 5) as shown in FIG. A ground layer 54 constituting a ground circuit may be formed.

(Insulating film)
The insulating film 51 preferably has a surface resistance of 1 × 10 ⁶ Ω or more.
The insulating film 51 is preferably a heat resistant film, and for example, a polyimide film, a liquid crystal polymer film, or the like can be used.
In order to ensure the strength of the flexible printed wiring board 41, the thickness of the insulating film 51 is preferably 5 μm or more, more preferably 6 μm or more, and even more preferably 10 μm or more. Further, the thickness of the insulating film 51 is preferably 50 μm or less, and more preferably 25 μm or less in order to obtain a flexible printed wiring board 41 having good flexibility.

<Method for producing flexible printed wiring board>
Next, the manufacturing method of the flexible printed wiring board shown in FIG. 5 is demonstrated as an example of the manufacturing method of the flexible printed wiring board of this invention.
To manufacture the flexible printed wiring board 41 shown in FIG. 5, first, the flexible printed wiring board main body 50 in which the wiring conductor is formed on the insulating film 51 is formed. In order to form the flexible printed wiring board main body 50, for example, a copper-clad laminate in which copper foil is bonded to both surfaces of the insulating film 51 with an adhesive is prepared. Examples of the copper foil of the copper clad laminate include a rolled copper foil and an electrolytic copper foil. From the viewpoint of flexibility, it is preferable to use a rolled copper foil. The thickness of the copper foil is preferably 3 to 18 μm.

Next, the copper foil on one surface on the copper clad laminate is etched by an existing etching method, and a pattern having a desired shape corresponding to the wiring conductor 53 is formed on one surface of the insulating film 51. Also, the copper foil on the other surface of the copper clad laminate is etched by an existing etching method, and a ground layer 54 having a pattern of a desired shape corresponding to the ground circuit is formed on the other surface of the insulating film 51. To do.
The flexible printed wiring board body 50 is formed by the above process.

  Next, the electromagnetic wave shielding film 11 shown in FIG. 1 is attached to the flexible printed wiring board body 50 in which the wiring conductor 53 is formed on the insulating film 51. Specifically, it is arranged on the flexible printed wiring board main body 50 so that the adhesive layer 30 of the electromagnetic wave shielding film 11 is in contact with the flexible printed wiring board main body 50 (the surface opposite to the release film 20 is opposed). Then, the electromagnetic wave shielding film 11 is stuck on the flexible printed wiring board main body 50 as shown in FIG. 6 by heating and pressurizing as necessary.

Thus, the adhesive layer 30 fills the space between the wiring conductors formed on the surface of the flexible printed wiring board main body 50 and bonds the flexible printed wiring board main body 50 and the electromagnetic wave shielding film 11 together.
Thereafter, the release film 20 is peeled off.
The flexible printed wiring board 41 shown in FIG. 5 is obtained by the above process.

  In addition, in the flexible printed wiring board 41 shown in FIG. 5, although the case where the flexible printed wiring board main body 50 and the electromagnetic wave shielding film 11 were adhere | attached directly was mentioned as an example, the manufacturing method of the flexible printed wiring board of this invention was demonstrated. And a flexible printed wiring board is not limited to said example.

  FIG. 7 is a sectional view showing another example of the flexible printed wiring board of the present invention. 7 is different from the flexible printed wiring board 41 shown in FIG. 5 only in that a coverlay film 60 is provided between the flexible printed wiring board main body 50 and the adhesive layer 30. About the same member as the flexible printed wiring board 41 shown in FIG. 5, the same code | symbol is attached | subjected and description is abbreviate | omitted.

  In the flexible printed wiring board 42 shown in FIG. 7, the electromagnetic wave shielding film 11 is attached to the flexible printed wiring board main body 50 through the cover lay film 60 so that the adhesive layer 30 is in contact with the cover lay film 60. . In this case, the flexible printed wiring board 42 in which the coverlay film 60 is disposed between the flexible printed wiring board main body 50 and the adhesive layer 30 is obtained, and between the flexible printed wiring board main body 50 and the adhesive layer 30 is obtained. Can be insulated more reliably.

  Moreover, in this embodiment, since the electromagnetic wave shielding film 11 can obtain an electromagnetic wave shielding function without connecting the shield layer 27 to the ground circuit of the flexible printed wiring board 42, the coverlay film 60 is processed. The coverlay film 60 can be disposed between the flexible printed wiring board main body 50 and the adhesive layer 30 without performing the step of performing.

The coverlay film 60 is not particularly limited, and examples thereof include those in which an adhesive layer 61 and an insulating layer 62 are provided in order from the flexible printed wiring board body 50 side.
Examples of the adhesive layer 61 include epoxy resin, polyester, polyimide, polyamideimide, polyamide, phenol resin, polyurethane, acrylic resin, melamine resin, polystyrene, and polyolefin.
Examples of the insulating layer 62 include resins such as polyimide, liquid crystal polymer, polyamide, polyphenylene sulfide, polyamideimide, polyetherimide, polyethylene naphthalate, and polyethylene terephthalate.

Furthermore, the flexible printed wiring board of this invention may be provided with the coverlay film on the opposite side to the electromagnetic wave shielding film 11 of the flexible printed wiring board main body 50, for example.
The coverlay film is not particularly limited, and examples thereof include those in which an adhesive layer and an insulating layer are provided in this order from the flexible printed wiring board main body 50 side. As the adhesive layer and the insulating layer, the same one as the coverlay film 60 shown in FIG. 7 can be used.
In this case, the surface of the flexible printed wiring board main body 50 opposite to the electromagnetic wave shielding film 11 is protected by the coverlay film.

  The electromagnetic wave shielding films 11 to 13 of the present embodiment are all formed on the release film 20, include insulating particles inside, and have a convex portion derived from the insulating particles on the surface opposite to the release film 20. It includes a resin layer, a shield layer 27 made of a conductive material and formed by physically depositing a metal on the insulating resin layer, and an adhesive layer 30 formed on the shield layer 27. Therefore, in the electromagnetic wave shielding films 11 to 13 of the present embodiment, the shield layer 27 has a high resistance portion 27b having a high surface resistance and a low surface resistance due to a difference in thickness of the shield layer 27 caused by the convex portion of the insulating resin layer. A low resistance portion 27a is formed.

  Therefore, in the electromagnetic wave shielding films 11 to 13 of the present embodiment, electromagnetic wave noise flows as a high-frequency current through the low resistance portion 27a of the shield layer 27, and is lost and attenuated in the high resistance portion 27b. That is, the electromagnetic wave shielding films 11 to 13 of the present embodiment can obtain an electromagnetic wave shielding function without connecting the shield layer 27 to the ground circuit of the flexible printed wiring board 41.

  Moreover, since the insulating resin layer is formed on the release film 20 and includes insulating particles inside the electromagnetic wave shielding films 11 to 13 of the present embodiment, the insulating resin 21 a and the insulating particles 21 b are formed on the release film 20. By the method of apply | coating the coating liquid containing this, the insulating resin layer which has the convex part derived from an insulating particle on the surface can be formed easily and efficiently. And the shield layer 27 which has thickness dimension distribution based on the convex part of an insulating resin layer can be easily formed by vapor-depositing a metal physically on an insulating resin layer.

  Moreover, in the electromagnetic wave shielding films 11 to 13 of the present embodiment, it is not necessary to impart conductivity to the adhesive layer 30 in order to connect the shield layer 27 to the ground circuit. Therefore, the adhesive layer 30 can function as an insulating layer, and it is necessary to provide an insulating layer for insulating the adhesive layer 30 and the flexible printed wiring board body 50 in addition to the adhesive layer 30. In addition, the flexible printed wiring board 41 can be thinned.

Examples are shown below. The present invention is not limited to these examples.
(Thickness of each layer)
Using a transmission electron microscope (H9000NAR, manufactured by Hitachi, Ltd.), the cross section of the electromagnetic wave shielding film was observed, and the thicknesses of five portions of each layer were measured and averaged.

(Average surface resistance)
Using two thin-film metal electrodes (length: 10 mm, width: 5 mm, distance between electrodes: 10 mm) formed by depositing gold on quartz glass, an object to be measured was placed on the electrodes, and from above the object to be measured, A 10 mm × 20 mm region of the object to be measured was pressed with a load of 50 g, the resistance between the electrodes was measured with a measurement current of 1 mA or less, and this value was taken as the surface resistance.

(Evaluation of transmission attenuation characteristics of shield layer)
The transmission attenuation characteristics of the shield layer were measured using a coaxial tube type shield effect measurement system (manufactured by Keycom) that measures the shield effect with a plane wave in accordance with ASTM D4935.

[Example 1]
The electromagnetic wave shielding film 11 shown in FIG. 1 was produced as follows.
A coating solution containing insulating resin 21a and insulating particles 21b was applied to one side of a release film 20 made of a polyester film of 80 mm × 80 mm × thickness 12.5 μm at a thickness of 8 μm and cured by heating.
In addition, a coating liquid uses the thing of the average particle diameter which consists of spherical and transparent heat-crosslinking acrylic resin as insulating particle 21b, and 5.1 micrometer, and uses the main ingredient and the hardening | curing agent containing the epoxy resin before hardening as insulating resin 21a, A mixed solvent of toluene and isopropyl alcohol was used as the solvent. The ratio of the solid content in the coating solution was 55% by weight. The concentration of the insulating particles 21b in the solid content was 0.15% by weight.

  Thus, the thickness (T) of the area | region which consists only of insulating resin by planar view of the obtained insulating resin layer 21 was 4.4 micrometers, and the largest dimension was 5.9 micrometers.

  A shield layer 27 was formed on the insulating resin layer 21 by physically depositing aluminum by magnetron sputtering. The minimum dimension of the thickness of the obtained shield layer 27 was 21 nm, and the maximum dimension of the thickness of the shield layer 27 was 73 nm, which had an uneven thickness. The average surface resistance was 0.28Ω.

  FIG. 8 is a three-dimensional (3D) image of the electromagnetic wave shielding film of Example 1 during production. The three-dimensional image shown in FIG. 8 is created from a photograph of the surface of the shield layer taken using a laser microscope at the stage where the process up to the formation of the shield layer is completed. The dimension in the planar direction of the 3D image shown in FIG. 8 is 256 μm in length and 256 μm in width, and the dimension in the vertical direction is 2 μm. As shown in FIG. 8, a concavo-convex shape based on the convex portion of the insulating resin layer 21 was formed on the surface of the shield layer 27.

Thereafter, an adhesive layer 30 made of an epoxy resin and having a dry film thickness of 25 μm was formed on the shield layer 27.
The electromagnetic wave shielding film 11 of Example 1 was obtained by performing the above process.

  The transmission attenuation characteristics of the shield layer of the electromagnetic wave shielding film 11 of Example 1 obtained in this way were evaluated. As a result, it was -54 dB.

[Example 2]
The electromagnetic wave shielding film 12 shown in FIG. 2 was produced as follows.
A coating solution containing insulating resin 22a and insulating particles 22b is applied to one side of a release film 20 made of a polyester film having a size of 80 mm × 80 mm × thickness 12.5 μm, and is cured by heating to a thickness of 6 μm. An insulating resin layer 22 was obtained.

  The coating liquid uses spherical and transparent thermally crosslinked styrene resin having an average particle diameter of 1.5 μm as the insulating particles 22b, and the insulating resin 22a uses a main agent and a curing agent containing an epoxy resin before curing, A solvent composed of a mixed solvent of toluene and isopropyl alcohol was used. The ratio of the solid content in the coating solution was 50% by weight. The concentration of the insulating particles 22b in the solid content was 2.5% by weight.

  The thickness (T) of the region made of only the insulating resin in a plan view of the other insulating resin layer 22 thus obtained was 3.0 μm, and the maximum dimension was 3.2 μm.

Subsequently, a coating solution containing an insulating resin 23a and insulating particles 23b was applied on the other insulating resin layer 22 to a thickness of 5 μm, and was cured by heating to obtain an insulating resin layer 23.
In addition, a coating liquid uses the thing of the average particle diameter of 4.5 micrometer which consists of spherical heat-crosslinking phenol resin as the insulating particle 23b, uses the main ingredient and the hardening | curing agent which contain the epoxy resin before hardening as the insulating resin 23a, and uses it as a solvent. A mixed solvent of toluene and isopropyl alcohol was used. The ratio of the solid content in the coating solution was 55% by weight. The concentration of the insulating particles 23b in the solid content was 0.2% by weight.

  Thus, the thickness (T) of the area | region which consists only of insulating resin by planar view of the insulating resin layer 23 obtained in this way was 2.8 micrometers, and the largest dimension was 5.3 micrometers.

  A shield layer 27 was formed on the insulating resin layer 23 by physically depositing copper by magnetron sputtering. The minimum dimension of the thickness of the obtained shield layer 27 was 70 nm, and the maximum dimension of the thickness of the shield layer 27 was 210 nm, which had an uneven thickness. The average surface resistance was 0.09Ω.

Thereafter, an adhesive layer 30 made of an epoxy resin and having a dry film thickness of 10 μm was formed on the shield layer 27.
The electromagnetic wave shielding film 12 of Example 2 was obtained by performing the above process.

  Thus, the transmission attenuation characteristic of the shield layer of the electromagnetic wave shielding film 12 of Example 2 obtained in this way was evaluated. As a result, it was -66 dB.

Example 3
The electromagnetic wave shielding film 13 shown in FIG. 3 was produced as follows.
A coating solution containing an insulating resin (solid content concentration 45% by weight) is applied to one surface of a release film 20 made of a polyester film of 80 mm × 80 mm × thickness 12.5 μm, and cured by heating to a thickness of 5.5 μm. Thus, another insulating resin layer 28 made of an epoxy resin was obtained.

Subsequently, a coating solution containing the insulating resin 21a and the insulating particles 21b was applied on the other insulating resin layer 28 to a thickness of 4 μm, and heated and cured to obtain the insulating resin layer 21.
In addition, the coating liquid for forming the insulating resin layer 21 uses a spherical and transparent thermally crosslinked acrylic resin having an average particle diameter of 3.2 μm as the insulating particles 21b, and polyetherimide as the insulating resin 21a. In addition, a solvent composed of N-methylpyrrolidone was used as a solvent. The ratio of the solid content in the coating solution was 55% by weight. The concentration of the insulating particles 21b in the solid content was 0.45% by weight.

  Thus, the thickness (T) of the area | region which consists only of insulating resin by planar view of the obtained insulating resin layer 21 was 2.2 micrometers, and the largest dimension was 3.7 micrometers.

  A shield layer 27 was formed on the insulating resin layer 21 by physically depositing copper by magnetron sputtering. The minimum dimension of the thickness of the obtained shield layer 27 was 25 nm, and the maximum dimension of the thickness of the shield layer 27 was 73 nm, which had an uneven thickness. The average surface resistance was 0.3Ω.

Thereafter, an adhesive layer 30 made of an epoxy resin and having a dry film thickness of 10 μm was formed on the shield layer 27.
The electromagnetic wave shielding film 13 of Example 3 was obtained by performing the above process.

  The transmission attenuation characteristics of the shield layer of the electromagnetic wave shielding film 13 of Example 3 obtained in this way were evaluated. As a result, it was -56 dB.

  The flexible printed wiring board manufactured using the electromagnetic wave shielding film of the present invention is useful as a flexible printed wiring board for small electronic devices such as an optical transceiver, a mobile phone, a digital camera, a game machine, and a notebook computer.

DESCRIPTION OF SYMBOLS 11 Electromagnetic shielding film 12 Electromagnetic shielding film 13 Electromagnetic shielding film 20 Release film 21 Insulating resin layer 22 Other insulating resin layers 23 Insulating resin layer 27 Shielding layer 28 Other insulating resin layers 30 Adhesive layers 41, 42 Flexible printed wiring board 50 Flexible Printed Wiring Board Body 51 Insulating Film 53 Wiring Conductor 54 Ground Layer 60 Coverlay Film 61 Adhesive Layer 62 Insulating Layer

Claims (10)

An insulating resin layer formed on a release film, including insulating particles therein, and having a convex portion derived from the insulating particles on the surface opposite to the release film;
A shield layer made of a conductive material, formed by physically depositing metal on the insulating resin layer;
An electromagnetic wave shielding film comprising an adhesive layer formed on the shielding layer. The average particle diameter (D) of the insulating particles and the thickness (T) of a region made of only an insulating resin in a plan view of the insulating resin layer satisfy the following formula (1). Electromagnetic shielding film.
0.5T ≦ D ≦ 2T (1)   The electromagnetic shielding film according to claim 1 or 2, wherein an average particle diameter of the insulating particles is in a range of 1 to 15 µm.   The electromagnetic shielding film according to claim 1, wherein the insulating particles are transparent.   The electromagnetic wave shielding film according to claim 1, wherein at least one other insulating resin layer is provided between the release film and the insulating resin layer. .   6. The electromagnetic wave shielding film according to claim 5, wherein the insulating resin contained in the insulating resin layer is higher in hardness than the insulating resin contained in the other insulating resin layer.   The electromagnetic shielding film according to claim 5 or 6, wherein another insulating resin layer in contact with the release film contains transparent particles. An insulating resin layer having a convex portion derived from the insulating particles on the surface opposite to the release film by applying a coating liquid containing insulating resin and insulating particles on the release film, including insulating particles inside An application process for forming
A vapor deposition step of forming a shield layer made of a conductive material by physically depositing a metal on the insulating resin layer;
And a step of forming an adhesive layer on the shield layer. The flexible printed wiring board body in which a wiring conductor is formed on an insulating film, the electromagnetic wave shielding film according to any one of claims 1 to 7, and the adhesive layer on the flexible printed wiring board body. A process of adhering to contact,
And a step of peeling the release film. A method for producing a flexible printed wiring board, comprising: The electromagnetic wave shielding film according to any one of claims 1 to 7, wherein the adhesive layer is formed on a flexible printed wiring board body in which a wiring conductor is formed on an insulating film via a coverlay film. A process of adhering to the cover lay film;
And a step of peeling the release film. A method for producing a flexible printed wiring board, comprising: